Create a default tmux session only when none defined in tmux.conf

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Support $PYTHONUSERBASE per PEP 370

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
[utility] no confirmation on rm, mv, ln...
[git] no aliases
[pacman] source yaourt script
[pacman] custom yaourt upgrade
[utility] alias _=‘sudo -E’
[external] updates