Fixed bugs in tag editor

This commit fixes bugs related to the user creating custom tags and
choosing from default tags. Previously, a user was able to add more
than four tags and add disabled tags. We also styled .btn-disabled
to not changea appearance on hover.

The tag text parsing code now utilizes data attributes to fix the bug
where html entitites were being encoded.
Removing useless comment
Merge pull request #1 from mholubowski/summer-features

Fixed bugs in tag editor