MultiColumnGridLayout: removed for now
TextArea: support for backgroundFocusedSkin (closes #557)
TextInput: docs fix
TextFieldTextEditorViewPort: fix for measurement (used wrong textfield)
Scroller: better measurement so that autoSizeIfNeeded() can be overridden. TextArea: overrides autoSizeIfNeeded to use the background skin's bounds instead of content.
Got rid of compiler warnings (closes #504)