[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>
First pass at prezto configuration
Update README.md
More fun times
Disable diff hilite for commands
Add ssht()
A few changes