FEATURE Added Widget_Controller class to enable nested forms within Wiget class.
ENHANCEMENT Changed WidgetArea.ss to iterate over $WidgetControllers instead of $Widgets, to allow forms rendered within to retain their controller context (through Widget_Controller and $failover mechanisms).
ENHANCEMENT Added handleWidgets() to ContentController to support new Widget_Controller class
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@85789 467b73ca-7a2a-4603-9d3b-597d59a354a9