change border color of windows when focused?

Hey people,

I've been trying for a long time to get borders around windows, and I've been failing. I'm putting out a call for help as the XCB version of sowm is being written, and I'm using Xlib, so please keep that in mind.

I've been trying to put border change functions in ```win_focus```, ```map_request```, etc.

Please point me in the right direction. Thanks.