Making the Makefile build output nicer

Xilinx's tools are really spammy, xob has a version of colormake which works with them. This uses that tool (with a small addition to prevent colorizing when being piped).

![screenshot from 2014-07-25 16 29 59](https://cloud.githubusercontent.com/assets/21212/3698793/50402e6a-13c9-11e4-880f-146fbdbc1599.png)