Clean up functions; add functionality to bookmark files

This fixes some quoting, refactors jarvis_jump & jarvis_cd, adds the ability to bookmark files in jarvis_add, and changes the parameter numbering for the functions. Review and test the code to make sure the changes are in accordance to how you want to handle bookmarks, especially with jarvis_add.

Tested on zsh 5.0.5, zsh 4.2.10, and bash 4.3.0. Cheers!