Linking Tag Controller to Tag Views

This pull request contains changes that link the Tag Controller to Tag Views. Currently the following features have been implemented:
* Tag table in Views/Tags/index.html.erb is now working (~~more work needs to be done on the tag links.~~ Links for editing and deleting now work.)
* Modifications have been made to the Tag controller to support creation, deletion and grouping features.
* A Tag helper has been created to allow for Ajax querying of the ActiveRecord.

Currently, not much testing has been done. This is currently a work in progress.
There is a NoSuchError method here (found when running rake test:functionals).