This adds two new Terminal classes. It's separated into two, so that opening
a split inside a tmux window is preferred to the other terminal types, but
opening a tmux session is prioritized only slightly higher than screen.
- tmuxrunning: Open a new pane in the current running tmux window. Requires
that the TMUX variable be added to the env whitelist to use it.
- tmux: Open a new tmux session
Signed-off-by: Christopher Larson <chris_larson@mentor.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
