Checks/Adds 'Revision" Support to CPTs Automatically

This simply checks the post type to see if revisions are supported, and adds support for them if they do not support them at the time of load.
Check if CPTs Support Revisions Before Adding to Settings

Added a check for support of revisions within each post type to prevent users from enabling forking on post types that don't support revisions.
https://github.com/post-forking/post-forking/pull/61#issuecomment-23239862
Updated Inline Comments for get_potential_post_types() Function
Merge pull request #61 from josh-rathke/patch-1

Checks/Adds 'Revision" Support to CPTs Automatically