* use element applies referenced viewBox scaling
* created FontManager

- suppress warning CS1591: Missing XML comment for publicly visible type or member
  to avoid to overflow the build log with warnings
- fixed the rest of the documentation warnings in SVG project
- ignore all failing tests for the time being

- fixes text-text-12-t.svg

- use GetInheritedAttribute() to correctly handle "Inherit" value
- fixes inheritance of these attributes from groups
- fixes alignment in types-basic-01-f.svg test

This reverts commit a7097113.

This reverts commit 480a54d8.

Based on Issue #204.
Now users can add customer fonts/ private fonts to
SvgElement.PrivateFonts.

Unit Test:
Add Test: PrivateFontsTest
Add Resources from PrivateFontsTest.
Add SvgTestHelper
Change MultiThreadingTest, now based on SvgTestHelper to use shared code
(no code duplication)

Note:
MuliThreadingTest TestFile is not available. The vvvv/master should add
the test file to the resources or other developer can not test the svg
engine.

Load an attribute only once if possible.

Fix:
Now the application make sure to set back the old culture even an error
occurred.
SvgColourConverter.ConvertFrom
SvgPathBuilder.ConvertTo
SvgDocument.Write
SvgExtentions.GetXML

Add:
Attribute: "shape-rendering"

Change:
- Many other properties were unknowingly overloaded. I changed them to
override.
- Some methods or structures need the [CLSCompliant(false)] Attribute.
For example the Enums.TryParse extension. This extension has the where
condition IConvertible. IConvertible is [CLSCompliant(false)] and that
the reason why it is correct to mark the Enums.TryParse extension also
as [CLSCompliant(false)].
- Property "float Opacity" in SvgElement was unknowingly overloaded in
SvgGradientStop as string [stop-opacity]. In the end this property was
only used as float. I changed the SvgGradientStop.Opacity property from
string to float and to override.

Fixed many attribute enums. Now they will 1) output the proper case, 2) only output if non-null and non-default, 3) include more documentation, 4) are marked as Flags where appropriate.

Fixed many attribute enums. Now they will 1) output the proper case, 2) only output if non-null and non-default, 3) include more documentation, 4) are marked as Flags where appropriate.

Added parameter to the SvgAttribute indicating whether the storage is
the _attribute dictionary.  If true, the output will only be serialized
only if the key is in the dictionary.  This structure is an alternate to
the SvgDefinitionDefaults class.

- Improving rendering of SVG images
- Allow markers on lines, polygons, and polylines
- Implement different line joins and line caps
- Improve CSS handling

- Better parser for dealing with parsing edge cases
- Fix corner radius for rectangles
- Fix to gradients.  Most tests now pass
- Add the possibility for a fallback paint server
- Initial fixes to clipping
- Start marking passed test
- Fixes to pattern rendering

- Extraction interface for SvgRenderer
- Initial support for Text on a Path
- Initial support for Svg Fonts
- Support for symbol element
- Minor bug fixes with image pattern rendering
- Additional support for Text whitespace modes

- Support of generic fonts (serif, sans-serif, monospace)
- Initial support of filters
- Fixes to gradient rendering

- Remove WPF dependency
- Fix compilation error after merge
- Add support for underline and strike through
- Fix whitespace handling with text rendering

- Adding W3C test cases and a test fixture
- Fixed support for CSS stylesheets (particularly when class names are
referenced)
- Refactoring unit calculations so that percentages and fractions
calculate more accurately
- SvgImage:
- Support PreserveAspectRatio attribute
- Support for referencing svg images
- Refactored text rendering to use the AttributeCollection inheritance
scheme
- Initial attempt at 'ex' unit support
- Added support for system color names
- Changed parsing of entities to support XML entities
- Supporting loading of a svg document directly from a XmlDocument with
requiring serializing the document as a string first.
- ...

- Support more font styles
- Fix problems with parsing 'em' svg units introduced by trying to parse
2e-5 double formats
- Move font properties to SvgVisualElement class as grouping elements
can also contain them
- Properly inherit font properties via the parent list
- Properly handle tspan offsets
- Support for .Net 3.5

Moved Display="none" hack & Added .Render check for : if (!Visible ||
!Displayable)

Also, minor change to logic of SvgBoolConverter so bad visibility values
(other than "hidden" or "collapse") wouldn't accidentally hide element

* fill can be null -> none in XML
* added type converters for enums
* added type converter for unitcollection
* fixes several viewbox bugs
* document can now draw into a given bitmap
* content of SVG tag is written (used by the text tag)
* changed font handling in text element, still need proper alignment
* changed intersparse character of SvgTransformConverter.cs to space, because inkscape couldn't parse comma
* added class diagram for basic shapes

- Fixed a bug that caused <text/> elements to be parsed incorrectly, leading to exceptions within the document.

- Changed the ISvgStylable interface StrokeDashArray property to be of type SvgUnitCollection instead of     SvgUnit[] and updated SvgGraphicsElement to implement this change.

- Fixed #6324: SvgElement.PushTransforms and ViewBox - not necessarily related to ViewBox but every   element was 'resetting' the current graphics transform if the element contained it's own transform. This 
  was a very small fix for a large problem (SvgElement.PushTransforms Matrix transformMatrix = new   Matrix(); changed to Matrix transformMatrix = renderer.Transform; in order to inherit the current   transform.)
- Fixed #6344: Parsing document incorrectly parents elements when it encounters empty nodes which are   in a different namespace. Empty nodes are now ignored and current nodes are closed as required. We'll 
  see how this fix goes.
- Fixed #6381: Units in inches are incorrectly parsed as millimeters - problem was caused by some   copy/paste work.
- Graphics has been replaced by SvgRenderer. This is essentially a wrapper around graphics but will allow
  custom svg related properties in the future when needed.
- Removed ISvgRenderer: A concrete implementation is suitable.
- SvgElement.ElementName has been changed to non-virtual and is set by the parser instead of the   developer having to specify it when developing the class.
- Added more XML API documentation.