Added custom bash prompt, based on the 'my' theme.
Added custom bash prompt, based on the 'my' theme.

This colors the arrow at the start of the second line based on the exit
code of the last command: green for 0, red for non-zero

This functionality currently fails when the 'fasd' plugin is enabled,
since it is messing with the PROMPT_COMMAND function.

prajnak/bash_it