Allows USE_WHITELIST to be set vi template

Adds documentation to README.md

Remove trailing commas in metadata.json

The commas after operatingsystem compatiblity expressions created
invalid JSON that could not be properly built into a release tarball.
This commit removes each. A future commit could remove all but
operatingsystem_support from the root metadata.json and the result
of puppet module build would still produce the right metadata.

Bumps version and corrects md5sums
Merge pull request #50 from scottsuch/variablize_use_whitelist_config

Allows USE_WHITELIST to be set vi template