Refactor terminal PS1

* Explicitly, globally export colors in bashrc
* have git_ps1_lopopolo echo its return value
* capture git_ps1 return value via a subshell instead of global variables
* consistently name PS1 building vars with all caps
* factor out some PS1 components for readability
Remove hyperbola from CDPATH
Ignore keepassx files
Move growl function to mac bashrc