[GTK,WPF] ListViewColumn: add support to set the alignment of the title
Extend color selector example
[GTK] add color selector backend
fix HSL conversion in DefaultColorSelectorBackend
extend DefaultColorSelectorBackend
* replace text entries with spin buttons
* add opacity slider
add ColorPicker button with a default xwt based backend
[GTK] add color picker backend
[GTK] use system default title in SelectColorDialog, if no title is specified
Merge branch 'master' into listviewcolumn-alignment
[WPF] Util: keep the original formatting
[WPF] Util: fix line endings
[MAC] fix toggle button
 * add OnToggled event
 * use NSButtonType.PushOnPushOff
extend button sample with some ToggleButton toggle actions
[MAC] mark ButtonBackend.SetButtonStyle as virtual
(was missing in @2070102)
fix typo in button sample
#327 - fix save dialog window on mac
Merge remote-tracking branch 'mono/master' into add-color-selector-backends

Conflicts:
	Xwt.Gtk/Xwt.Gtk.csproj
Merge remote-tracking branch 'mono/master' into add-color-picker

Conflicts:
	Xwt.Gtk/Xwt.Gtk.csproj
	Xwt/Xwt.csproj
add TextEntry.PlaceholderText samples with different alignments
[WPF] fix PlaceholderText alignment and initialization