Add support for fossil scm

Conflicts:
	liquidprompt
Align liquid.theme with liquidprompt after first cherry pick
Add the number of impacted files in fossil repository
Add special color when current repository has no tag.
Re-add two auto-deleted line during cherry-picking
Changege the untracked behavior to the same as git. Fix branch display bug while browsing deep fossil repositories
Invert if order to speed up a bit the prompt display when parsing a fossil repository
Merge pull request #91 from milouse/develop

Add support for Fossil SCM (the return)