WM_TAKE_FOCUS support (for java applications)

Basic support for the WM_TAKE_FOCUS extension. Java applications will assume this extension is implemented by the WM, causing focus problems if it is not.

[scottjad](https://github.com/scottjad/) has seen issues with the borders not being recolored correctly and has a possible fix. I have been running with this patch for some time now and while java apps still have occasional focus weirdness or other glitches, I have not seen any regressions in previously working applications.