Fix for issue #16

Hi Bob

This should fix the tag rendering issue in tvs.

Since the topic is MODx tags, may I take the opportunity and ask, what you think about a more fine grained control over which tags can be edited by the user?
Sometimes I want to edit a doc containing a field tag or simple links, but NP would not allow it without allowing ALL tags. Therefore I have tried to make a prototype that parses the tags using the builtin tag parser and checks for additional permissions such as 'np_edit_links', 'np_edit_snippets', etc. This would allow users to edit/create "unproblematic" tags while editing snippets or chunks would still be forbidden. If you are interested, I could work it out a bit more and push the code to github.

Markus