create maps module
maps: remove default metabolites inline style

For metabolites with the default styling, use a stylesheet instead of
inline styles to make them easier to override.
external metabolites given own css class
refactor maps code

importing maps functions are now in their own script
another map added
Merge branch 'master' into maps
Merge branch 'master' into maps
Merge branch 'master' of github.com:opencobra/cobrapy into maps
Merge branch 'master' into maps
Merge pull request #2 from aebrahim/maps

New maps module