automatically version shell functions with git:
* treat all shell functions as micro shell scripts
* store functions as .sh files in a ~/.composure repo
* revise () edits functions from last commit state
* re-source functions from ~/.composure at any time, in any shell
numerous fixes and refactorings
* Only load a theme file if `bobby` has been set
* Only alter `PS1` if `\[[1;34m\]\[$(scm_char)\]\[[0;32m\]\[$(scm_prompt_info)\]\[[0;34m\]\[$(rvm_version_prompt)\] \[[33;40m\]\h \[[39m\]in \[[0;32m\]\w \[[39m\]\[\n\[[0;32m\]→\[[39m\] ` has a value