Added PreviewTextInput event with WPF implementation.
Added text input sample.
[Mac] Fix CanvasBackend MouseEntered, MouseExited, MouseMoved events

Add a TrackingArea to CustomWidgetBackend to capture events.  Also fixes these events for Boxes and other users of CustomWidget
Update CanvasWithWidget sample to show Mouse Enter, Exit and Move events
[Icons] Fix missing icon for search entry.
add XwtComponent.Tag property
#300: fixed tabs and replaced oldschool property with auto-implementing variant of one
[Mac] Fix events for Label, LinkLabel, TextEntry Backends,
and update WidgetEvents sample to demonstrate better

WidgetView has been moved into a separate file WidgetView.cs, to
handle and dispatch the events generated by NSView and its TrackingArea.
This is used as the base for CustomAlignedContainer for Label, etc.
[WPF] Defer calling Widget.Focus() until it is loaded

This fixes a weird issue where a TextBox would not appear at all
if Focus was called too early.
WPFBackend.KeyboardUtil: use refactoring-proof consts to calculate Key
Fix issue #289: unable to use StockIcons in Gtk ListView
Flush project changes
[GTK] Fix checkbox cell view issue

Fixes issue #293: cannot check CheckBox in ListView
Merge pull request #311 from atauenis/master

Add XwtComponent.Tag property
Merge pull request #312 from steffenWi/master

Allow Initialize without specifying the backend type
Merge pull request #299 from hwthomas/CanvasView

[Mac] Fix CanvasBackend MouseEntered, MouseExited, MouseMoved events
Merge pull request #317 from lytico/WpfKeysBuggy140403

WPFBackend.KeyboardUtil: calculation of keys is messed up
WPF.FileDialogBackend: check if no file selected
[GTK] use GtkInterop for all Interops
[GTK] add missing window icon support