This fixes the remaining Python 3 syntax errors, so re-enable compileall
for contrib/ again.

renamed plugins to contrib (they are not really plugins)
rewrote README.md to reflect new usage
added new dir to setup.py so it gets copied with installation, in views
of making using inventory scripts easier in teh future

rules are avaialble at https://en.wikipedia.org/wiki/Wikipedia:AutoWikiBrowser/Typos

The existing code was using:
  a[b][c[d]]
where a[b] would always exist and c[d] would always exist.
But the nested index would not alway exist, particularly when a DigitalOcean item disapeared.

This changes that nested index to a `get` and properly handles None results.

This bug was present in two spots in this file.

The `dopy` library function all_images includes a 'global' filter
by default.  This was preventing private images from showing up
in --images.

The problem also made this script fail immediately for people
who had droplets previously created with private images.

* Always refresh droplet information (versus getting it from cache) for
  --list, --host, --droplets, and --all.   All the DigitalOcean calls are
  pretty fast and without this change, inventory was often stale/incorrect.
  For example, previously if you destroyed a droplet, the inventory
  script would still find it and attempt to act on it.

* Added --force-cache option

* Added some option shortcuts -d, -r

* Added more value sanitization

Intended to complement the recently added digital_ocean module.