TagFiltrPlugin v.1.4.4 — tag groups & dynamic popup on CTRL + Click

Prefixes are replaced with more generic tag groups that work on tagging,
e.g. a group-tag: "task" has category tags "#next, #future, #waiting,
#done" to which actual tiddlers are tagging.

Now, when a tag in the tag-adder button is clicked using CTRL+click, the
popup is refreshed with whatever tags remain valid.