Upped version to 3.1

Added handling of invalid property in parser (svg-net#639)

* Fix: svg-net#632 'Does not render .svg properly' issue.
* Add tests.
* Update ReleaseNotes.md.

Fix: svg-net#592 'Converting from SVG to PNG doesn't include embedded…

… image' issue. (svg-net#606)

* Fix svg-net#592 'Converting from SVG to PNG doesn't include embedded image' issue.
* Support uppercase MIME type.
* Add tests.

include xml doxumentaion in nuget

include xml documentation in nuget

released nuget 2.4.3

nuget 2.4.2 release

added nuget 2.4.1

added nuget 2.4.0

Merge pull request svg-net#267 from vvvv/revert-198-master

Revert "Fix svg-net#176: Blurry text when overlapped with colored background"