Use g:tmuxcomplete#capture_args to in tmuxcomplete#words
Merge pull request #33 from wellle/words-capture-args

Use g:tmuxcomplete#capture_args to in tmuxcomplete#words
support tmux 1.6

- default capture_args with -J only if supported (tmux 1.7+)
- tmux 1.6 does not support -p (send to stdout), so work with
  paste-buffers instead.