bugfix: explicit globals for nested conditional imports

Python3 does not import at module level from within a function. Globals must be explicits.
python2 -> python3 in the README
Merge branch 'master' of http://github.com/nojhan/colout
Use 256-colors for scale in cmake theme
Merge branch 'master' of http://github.com/nojhan/colout
Silently handle broken pipes

Two errors could occur when using a command that break the pipe on which
colout is supposed to write, like head or tail:

    ls | colout . red | head -n 1

This fix set the SIGPIPE handler to kill the program instead of ending
in a write error when a broken pipe occurs and silently handle broken
pipes IOError exceptions.