[WPF] Try using WPF rendering api
Merge remote-tracking branch 'origin/master' into visual-render
Fixes in the context backend. Added missing files.
Merge branch 'master' into visual-render

Conflicts:
	Xwt.WPF/Xwt.WPFBackend/ImageViewBackend.cs
[WPF] Refactor code in context backend
[WPF] Fix figure filling issue
Merge branch 'master' into visual-render

Conflicts:
	Xwt.WPF/Xwt.WPFBackend/ImageViewBackend.cs
[WPF] Use a TransformGroup to keep track of applied transforms
[WPF] Remove all usage of System.Drawing
[WPF] Added test runner
[WPF] Fix some path drawing issues
[WPF] Improve the radial gradient
[WPF] Implemented GetPixel and SetPixel for bitmaps

Also, when loading an image convert it to 96 dpi if
it has a different dpi.
[WPF] Fix method for getting the native image
Merge remote-tracking branch 'origin/master' into visual-render

Conflicts:
	Testing/Tests/ReferenceImageManager.cs
Merge remote-tracking branch 'origin/master' into visual-render

Conflicts:
	Xwt.WPF/Xwt.WPFBackend/GradientBackendHandler.cs
[WPF] Fix several drawing issues with arcs
[WPF] Add missing reference test images
Improve checking of test images
Merge branch 'master' into visual-render