choppsv1

This diff is a modified version of a diff written by Rüdiger Sonderfeld.

The original diff can be found here:

http://emacs.1067599.n5.nabble.com/RFC-Add-tty-True-Color-support-tt299962.html

To enable the feature one must set one of 2 environment variables either
ITERM_24BIT or KONSOLE_DBUS_SESSION. The former will enable ITU T.416 mode, the
latter will use semi-colon seperators used by other terminals (and also
supported by iterm development branch).