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.
Add 'chris' theme
Update zsh prompt
Add custom dir to repo
Remove Climate aliases
Remove spec alias
Add irc alias for weechat-curses
Remove before and after context on grep alias
Add gap alias, remove grep alias
Add custom scripts to repository
Rename scripts to have correct load order
Remove unnecessary init scripts
Change LSCOLORS to better match Thayer color scheme