Cleanup to make things a bit clearer.
Begin work on tooltip support.
Add experimental and untested functionality for bringing elements to the top and back.
Add the beginning of tooltips to the standard library.
Have the default tooltip be invisible by default.
More work on tooltips.
Fix a tooltip bug.
Have tooltips use a contrast look.
Fix a bug where the shadow rendering data is not re-validated when the size of the element changes.
Add ability to unbind event handlers.