Issue: Some Wiki Links are Ignored

Wiki links via the following are ignored when keeping records of what links to what:

• using the category tag, when it is used by a prefix
• using the gallery tag to wrap multiple images, when gallery is not used by a prefix
• added by templates on the current page, when template is not used by a prefix

Fixed for the next release. The link parser now uses a wiki-link flag on the tag definition, rather than explicitly defining only certain kinds of tags for the parser. The code that turns the category tag off now first checks that it isn't in use by a prefix. The gallery and template tags are always opted-in now.