- Catch exceptions in event handler.

- originally provided by @ssteiger in #316

- fixes TestPrivateFront unit test (threw exception because the image
  had zero size, as the only element is a "use" element)

- vertical graphics context resolution has been used incosistently which leads to wrongly positioned texts when printing

- ignore textLength attribute if X attribute is list
- add test images

- fixed a few other tests by using the Svg DTD Resolver to avoid web requests

- 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

- Fix: adjustment is wrong in lengthAdjust='spacingAndGlyphs'.
- Add test images.

fixed SvgAttrribute reflection for .net core. (i guess Equals() function is called instead of Match() on this platform?)

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

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

# image opacity fix

Updated threading tests to use the resource file, updated the file loader in the test helper to be flagged as obsolete and changed the working of the multi-threading fail test since this is not always failing with the error while processing the SVG. If it's not failing now it will be flagged inconclusive.

Fix fill usage by passing Color.Transparent color

Fixed inproper use of UTF8Encoding. As it was written before, UTF8Encoding.Default actually returns base class static property Encoding.Default which is system's default ANSI code-page based encoding that is not UTF8.

Fix rendering error on 64 bit IIS, ColorBlend position must be betwee…

Fix scaling of Draw(width, height)

Test runner: minor GUI improvements

- moved passing/failed/other tests into separate tabs
- removed functionless menu
- changed title

Added test description in test runner

- show description for W3C tests

Add a text copy of the Ms-PL and update Markdown formatting

Fixed inheritance of  text-anchor and baseline-shift attributes

- 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

- ensures that #243 is fixed

Found better solution to SvgClosePathSegment tested with Tiger.

Reverted unneeded part of previous fix

- caused regression

Prevent crashes on zero length segments or paths

Correctly handle embedded SVG fragments without viewbox

- fixes __tiger.svg test image

- calculate svg element bounds considering child svg fragments
- consider svg fragment offset in bounds / dimensions
- do not create view box if none is defined
- fixes #244