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
Optimize _lp_battery: no sed
Merge pull request #87 from dolmen/fix/batt

Optimize _lp_battery: no sed
my way of shorting path was way slower than the one originally implemented

redoing the dirtrim feature though
git: fix variable leaks
_lp_git_branch: faster (less external programs calls)
no systematic setting of PROMPT_DIRTRIM
adding comments and documentation
optimisation : less operation
Merge pull request #88 from dolmen/fix/git

More efficient git parsing (2)
changing my mail
Add an option to hide the logged user

LP_USER_ALWAYS=1 will display the user, even if he is the same than the logged one.
Defaults to 1 (always display the user), set to 0 if you want to hide the logged user (it will always display different users).
Use a chroot() function

Fixes a warning:
-bash: local: can only be used in a function

A local variable can only be used inside a function.
The function is also unset after use.
Invert if order to speed up a bit the prompt display when parsing a fossil repository
Merge pull request #90 from LudovicRousseau/master

Fixes a warning: -bash: local: can only be used in a function