Try to solve the empty thumbnail on the tags tree.
Added images (and files) preview generation; popup when user selects a thumbnail on tags window.
Added getPreview.php file...
Begin job to handle tag permissions and category
Added function to alter tag group and permissions on hTags.php
Removed setting "only admin can edit tag" due to tag's permission introduction.
Added icon for user/group
Added tags priviledge handling
Minor cleanups
Modified menu icon.
Update hTags.php

Minor changes in prepared queries
Final develop commit