docs tweaks
AnchorLayoutData: docs fix
Scroller: better data invalidation handling and moved refreshScrollValues into loop (closes #379)
FeathersControl: added FeathersEventType.CREATION_COMPLETE after first validation.
Item renderers: properly checks for _data along with the existing check for _owner (closes #595)
LayoutGroup: implemented clipping (closes #591)
Scroller: support for minimum scroll positions less than 0 (closes #344)
Scroller: better handling of scroll bar offsets whenfloating
Item renderers: better measurement to account for NaN (closes #592)
Item renderers: added delayTextureCreationOnScroll property (closes #545)
Item renderers: stopScrollingOnAccessoryTouch is a proper getter and setter now.
Scroller: consolidated and improved scroll start, complete, scroll bar showing and hiding, interaction management, and events (closes #579)
ImageLoader: added loadingTexture and errorTexture (closes #436)
ImageLoader: docs for loadingTexture and errorTexture (references #436)
Scroller: better isScrolling handling (since touchBlocker may not exist and better scroll bar positioning with floating
Item renderers: better delayTextureCreation handling (references #545)
GroupedList: better handling of typical item renderer measurement (references #570)
TextFieldTextEditor: snapshot is properly hidden when text is cleared (closes #599)
StageTextTextEditor: can handle displayAsPassword without replacing text (closes #561)
TextInput: better prompt handling