emacs: bind "C-c R" to rotate-layout

accompanies "C-c r" as rotate-window
emacs: remove ace-jump-mode and drag-stuff
emacs: add sane-term

seems to be the best option for using terminals in emacs.
use "C-c T" to create a new terminal, and "C-c t" to cycle through
existing ones.
git: add global gitignore file