Support both --force and -force for halozsh-install.
Not sure why these were in macvim instead of mac.
Support p+ and p- for pristine views.

- Depends on AUTO_CD being on and …/$1 being before …/pristine/$1 in
  $cdpath (or …/pristine/$1 *not* being in $cdpath, althoug …/pristine
  may be).

branch halozsh-binary-experiment
Provide a meaningful work environment script.