tmux: Further fixes, gradually approaching perfection

- Set repeat timeout back to 1 sec from almost nothing, so repeat key
  bindings are actually useful
- Fixed problematic repeat key bindings by removing repeatability (-r)
  especially Ctrl-a, and arrows
- Vim bindings for pane select/resize switched to letter/Ctrl-letter to
  better match tmux default arrow/Ctrl-arrow behaviour
- Removed "Maximize pane" zoom hack, no longer necessary in Tmux 1.8+
  use `PREFIX z` for zoom instead
- Increased display-time