[RP] ANSI patch

[Joe Corneli]

I think it would be nice to be able to control backlighting for the
bar. In response to my feature request about this, Björn recommended
the ANSI patch from a while back.  

I'd like to vote that this actually go into the main body of code at
this point.  I'd definitely be willing to test it out and make it
work with the current code (I don't suppose it will be hard), but
what do people think about ANSI escapes for the bar at this point?

The use I have in mind for it is an improved version of the
cyclebuffer integration function.

Joe

CF. http://ratpoison.elektrubadur.se/ANSI_patch