* Repair calculate a percentage value
* Add percentage size tests

- fixes #331

- fixes #191

- fixes #58

- added "stroke-dashoffset" support
- added "painting-stroke-04-t" to "PassingTests" (csv/txt)
- fixes #388 

- 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

In <image> element, preserveAspectRatio attribute default value is 'xMidYMid meet'.

https://www.w3.org/TR/SVG11/coords.html#PreserveAspectRatioAttribute

# image opacity fix

- relative URL have not been loaded (example: masking-path-06-b.svg in test data)
- Updated passing tests (note: not all changes are related to the current fix)

see #281

These shapes now render their fill, even if StrokeWidth less or equals zero.

RenderStroke method won't render the stroke if StrokeWidth is less or equal zero.

- Changed SvgImage.Href property from Uri type to String to avoid UriFormatException if Uri contains too much data
- Changed GetImage to receive a string instead of Uri object.
  - Created a temp Uri object in method with substring of allowed length and using this to determine Uri characteristics

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.

The rectangle path width/height was computed using the full stroke width.
It should have been using the half stroke width instead.

Extended the Marker start/mid/end getters with a function to return null if the property was set to none. This will prevent nullpointer issues when having none as one of the items.

- Because querying the Bounds property of an ISvgBoundable or
  SvgVisualElement is expensive, we introduced an ImmutableBoundable that
  is used by the SvgRenderer. This class stores the bounds of the supplied
  ISvgBoundable so that multiple queries for the bounds do not hamper
  performance when rendering.

- Converted the Bounds property on ISvgBoundable and SvgVisualElement to a
  CalculateBounds method to indicate that it is an expensive operation
  that returns a new value each time it is called.

- Removed redundant ISvgBoundable Location and Size properties.

- Fixed a bug in SvgFragment.Path property by converting it to a method that
  indicates it returns a new GraphicsPath instance when called and by
  disposing of that instance in CalculateBounds. There are many more
  instances of GraphicsPath not being disposed in the code base but we did
  not address that here.

- 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

- Fixing path parsing algorithm to deal with nuanced arc cases and
hopefully improve performance
- Attempts at better memory management
- Working toward getting symbols to render correctly

- 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.
- ...