Update tmux.conf to take advantage of latest powerline changes

Signed-off-by: Rodrigo Belem <rodrigo.belem@gmail.com>
Update all git submodules when running setup.sh

Signed-off-by: Rodrigo Belem <rodrigo.belem@gmail.com>
Powerline scripts must be in PATH

Signed-off-by: Rodrigo Belem <rodrigo.belem@gmail.com>