Update tmux-related settings
zshrc tweaks

- add 'json' alias
- use <c-b> for <c-a> (conflict with tmux prefix)
Update neobundle

- also call it 'neobundle.vim' instead of 'neobundle'
Add some nice features for python in vim
Remove version lock on syntastic
Add YouCompleteMe (autocompletion engine)
Change movement mappings