ThemedControlHandler and ThemedContainerHandler. Sample/Test code coming in the next checkin :)
Test/Sample code for Themed control, and a related fix to the winForms TableLayoutHandler to handle indirection correctly. The test app now has a new section, Controls/Tab Control (Themed), that contains a themed tab control. This test currently works for the Windows platform. Other platforms need to be fixed similar to the way the Windows platform was fixed, to allow for Eto Control handlers to themselves be Eto Controls.