Fixing Issue #235 TreeView problem with overwriting selected values at Loaded event with default Items[0] value and not selecting TreeItem because Item was selected before TreeItem was because WPF is LazyLoading TreeItems for Items after Loaded event...
Added comments to code
Fixing Issue #263. Wpf.FrameBackend did not UpdateChildPlacement after setting new Content(child)
Removed part for delayed selecting of VisualItem because it should be solved more generally for all cases. So this pull now only contains fix for issue #235
Added some null checks
Adjust Drawing Origin for CairoContextBackend

Offset Context Transformation Matrix to allow for origin of ContextBackend.
Merge branch 'master' of git://github.com/hwthomas/xwt into hwthomas-master
[GTK] Canvas issue drawing fix

Adjust the drawing origin only when the canvas is not using its
own GdkWindow.
[WPF] Canvas: Clip the drawing area

Fixes issue when drawing outside the canvas bounds.
[Gtk] Fix Cairo pattern leak
Matrix: null-check Equals value
[WPF] Implement Scrollbar.ValueChanged

Based on a fix by Marko B.L.
[Mac] Fix Slider control orientation

Based on a fix by Marko B.L.
Merge pull request #275 from lytico/MatrixNullCheck140113

Matrix: null-check Equals value
Basic WebView added.
[Icons] Stock icons review
[Icons] Icon TODO review
[Icons] Icon TODO review
[Icons] Reverting my latest three commits
IWebViewBackend must extend IWidgetBackend.