Colorize build success/failure message.

Change-Id: I8901689876e65f5b72050c40e1580f167e49c2b0
envsetup.sh:Cleanup
Use /usr/bin/env to call python

Hardcoding the path to python instead of env is not recommended.  This
can break the build in some Linux environments that link /usr/bin/python
to python3.

Change-Id: I4c62eb391acc6d468ce24ac8640834e965e76e78
Don't set CCACHE_BASEDIR if its already set

 * enable use of shared ccache

Change-Id: Ic708a5d5169291d674b167aa2c87bf2c8adaafae