Added special prompt to api client's shell mode.
Added special prompt to api client's shell mode.

 * A blue (Galah) will appear in front of user's default prompt to give
   the user a visual cue that they are within a modified shell.

brownhead/galah,galah-group/galah,ucrcsedept/galah,galah-group/galah,ucrcsedept/galah,brownhead/galah,galah-group/galah,brownhead/galah,ucrcsedept/galah