Add python.el utilities for working with packages

These are intended to be added into Emacs trunk soon.
Add alert and rcirc-alertify
More multiple cursors commands to region bindings

Added bindings to `region-bindings-mode-map' for
`mc/skip-to-previous-like-this' and `mc/skip-to-next-like-this' to "P"
and "N" respectively.
X clipboard enhancements