Update fg.py
Update bg.py
Update fg.py
Use ECMA-048 names as defaults.

The old (incorrect) names are kept as an alias for backwards
compatability. Note that "brown" was replaced by "yellow", so
"yellow" no longer is "bold + brown".
Merge branch 'master' of https://github.com/tehmaze/ansi

Conflicts:
	ansi/colour/bg.py
	ansi/colour/fg.py