Maintenance
#CHANGE: Moved all classes to an appropriate sub-namespace of AdamsLair.WinForms, so you aren't forced to use an all-or-nothing "using" directive.
#CHANGE: Moved ControlRenderer to AdamsLair.WinForms.Drawing namespace and moved all of its helper classes to separate files.
#CHANGE: Properly split CheckBoxState into multiple enums.
#CHANGE: TiledView now uses a public event for ItemAppearance rather than a delegate to comply with WinForms.
#CHANGE: Better TiledView performance when ItemUserPaint or ItemAppearance are registered.