extend mercurial plugin to be more like git/svn

implement in_hg(), hg_get_branch_name(), hg_prompt_info(), and hg_dirty() for the mercurial plugin
named functions similar to subversion plugin, to give theme maintainers an easier life
Fixed missing retcode function
Uncomment l alias
eliminated unnecessary cd and failing substitution

Changing the working directory in a sub-subshell
does not change the working directory of the executing
shell.

The substitution was broken for me on _all_ my machines,
so I started looking into the business.
Adding a fix for the DISABLE_UNTRACKED_FILES_DIRTY option.
Add web-search plugin.

This plugin adds google, bing and yahoo commands to launch the default
web browser to do web search:

e.g.

    google oh-my-zsh
    bing what is zsh
Fixed recursion. Git not needed for it to work.

Avoid infinite `cd` loops under certain conditions. Try getting `.venv` from the current directory (not necessarily always using git)
Merge pull request #1839 from Kronuz/patch-1

Fixed recursion. Git not needed for it to work.
Merge pull request #1837 from xuhdev/web-search

Add web-search plugin.
Merge pull request #1775 from marcusmueller/fixupgradetool

fix for failing substition & eliminated unnecessary cd
Merge pull request #1834 from croach/disable_untracked_files_dirty_fix

Adding a fix for the DISABLE_UNTRACKED_FILES_DIRTY option.
fix the open command in linux using xdg-open
Merge pull request #1849 from lemieux/master

Fix for Jira plugin on Linux
Added alias for git clean
New plugin for git-repo (https://code.google.com/p/git-repo/)

Signed-off-by: Gaetan Semet <gaetan@xeberon.net>
Improvement in the git plugin

Signed-off-by: Gaetan Semet <gaetan@xeberon.net>
A cabal plugin based on the lein plugin
Fixed color on git prompt for superjarin theme
Adding testlog and prodlog.
Update README.textile

Add upgrade command to docs. I canceled the prompt once and went hunting for this so I could upgrade.