Much need update (see full commit message)

 - vim :
   - remove autochdir, lazyredraw, map K <Nop>
   - vim-rspec : add mappings, use Dispatch
   - plugins : add tpope's abolish & surround
 - tmux :
   - add Ctrl-{h,j,k,l} to move between panes
   - set renumber-windows on
 - git :
   - use tig for logs
   - add 'fix' alias