Added support for different button layouts.
Merge remote-tracking branch 'Harrigan/master'
Initial support of virtual scrolls on scrollviews

(Will be later needed for tableview/listview virtual scrolling)
Cleanup
Allow drag scroll for virtual scroll scrollviews
Added extendablepanel.

Removed panellist.
Reverted accordion.
Vertical layout ignores invisible.
Layouts children visibility support.
Accordion uses visibility instead of add/remove child.
Checkbox Event.CHANGE fixed.
Added child percentWidth to horizontalContinuousLayout.
Merge remote-tracking branch 'Harrigan/master'

Conflicts:
	samples/expandable_panel/application.xml
	src/haxe/ui/toolkit/containers/Accordion.hx
	src/haxe/ui/toolkit/containers/PanelList.hx
	src/haxe/ui/toolkit/controls/Image.hx
Merge pull request #58 from ProG4mr/master

ExtendablePanel, layout child visibility and others.
Accordion fix for allowing selection before ready

(and haxelib)
Style updates
Merge remote-tracking branch 'upstream/master'