Laid out the groundwork for MORE improvement...
Began migrating the Windows code away from using container entirely. This is going to be a mess for Tab... hopefully only a short-term one.
More TODOs.
Reimplemented Control.containerShow()/Control.containerHide(). Will be needed to fully move Tab on Windows away from container.
Got rid of Tab's use of container on Windows.
Reverted to resizing all tabs equally; keeps code simple.
De-container-ized Stack.
Removed container from SimpleGrid and Grid. This is necessary to do now, alas; the Windows gouicontainers left over weren't being hidden, causing undesirable Tab behavior.
Added sharedWndProc() to Tab on Windows.
Removed the gouicontainer window class from the Windows backend; it is no longer needed.
Fixed Group on Windows not sending events to children. I /think/ we're done with container madness on the Windows backend...
More TODOs.
Migrated the GTK+ backend to the new new container system in which containers are no longer full controls but are still used to hold more than one control and handle the resizing entirely on their own.
More TODOs.
Restructured container on Mac OS X likewise. Still have to test.
Fixed Mac OS X issues.
Updated the README and TODO lists.