Adding xobs's colormake for Xilinx tools.

Originally from
https://raw.githubusercontent.com/xobs/novena-ws2812b-fpga/master/synth/colormake.pl
@ af44c5c
Only colorize on interactive terminals.

(Or if COLORMAKE=force is on.)
Run output through colormake.
Merge pull request #69 from mithro/color-output

Making the Makefile build output nicer