[Fix #543] Do not set tmux destroy-unattached

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Fix git-info added/deleted count formatting typo

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Merge branch 'master' of github.com:sorin-ionescu/prezto

Conflicts:
	modules/tmux/README.md
	modules/tmux/init.zsh
	runcoms/zpreztorc