Rename GridLines property to GridLinesVisible
Merge remote-tracking branch 'mono/master' into sevoku/add-list-gridlines

Conflicts:
	Xwt/Xwt.Backends/IListBoxBackend.cs
Merge pull request #338 from sevoku/add-list-gridlines

Add GridLines property to List/Tree views
[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
Merge branch 'fix-mac-toggle-button'

Conflicts:
	Xwt/Xwt.Backends/IListBoxBackend.cs