Starting to add topic tags for grouping content.
I need to test this out in some of our publishers to see how this works practically.
Merge branch 'master' into adding_tags
Changing TopicTag to MetaData
Merge branch 'master' into adding_tags
Making a few more objects mettable.
Renaming some things to clarify their function.
Merge pull request #116 from biola/adding_tags

Adding tags