- add function "composer"
- uses local composer if available
- add function "composer_install" to install composer to current dir

… due to performance concerns.

See #258
See #262

Send along the directory where we already found the .hg to throw hg a bone.

Conflicts:
	themes/bobthefish/fish_prompt.fish

Conflicts:
	themes/bobthefish/fish_prompt.fish

Add support for --bold (and --underline) to the __bobthefish_start_segment function.

 * Show the closest parent repo if $PWD is in both an hg and git repo.
 * Only find the repo root once per SCM, not two or three times :)

 * Inline a one-line method that's called one place
 * Make sure __bobthecow_virtualenv_python_version doesn't fail if python isn't a symlink.
 * Add a visual segment indicator after python version glyph.

remove some additional unnecessary complication.