[emacs mode] migrate to cl-lib.el

cl.el has been deprecated and cl-lib.el is the recommended choice for Common Lisp support within Emacs which properly namespaces all new symbols (cl-*).

Migrate both tern-auto-complete.el as well as tern.el.

Users of Emacs <24.3 can use the cl-lib.el shim from ELPA which should be automatically installed if tern is installed through an appropriate package repository like MELPA.

This also fixes issue #320 where the function call signature help was broken due to CL "find" being unavailable during runtime if cl.el was not globally available (which is not recommended).

The indentation fixes are nothing more than having Emacs properly indent everything after the changes to properly realign the affected blocks.