Added GUID field
Using shiva.dbtypes.GUID type
Updated documentation on ids and slugs
Adapted admin script to uuid
Adapted URLs and resources to the new ID type
Fixes to the admin script
Slugs cannot be used as IDs any more
Removing custom slugify method
Adapted tests to new id type
Added is_public confirmation to admin script
Trailing slashes

Resources now require trailing slashes. They were added because requesting a
resource with a trailing slash would 404. Now all resources without trailing
slash will be redirected.
Double slashes

Added a check to prevent double slashes errors.
Got rid of another with statement
Merge pull request #148 from tooxie/uuid

UUID