MCF format: Missing categories

Noticed some categories missing that could be useful:

* Superstition (probably with subcategories like tarot cards, fortune tellers, etc)
* Religion (per-religion subcategories? might need to support sub-subcategories?)
* Implied sexual relationships (especially homosexuality; some might even prefer to exclude all same-sex relationships of a certain affinity, even if not sexual in nature?)
* Sex subcategories for contraception and birth control
* Violence subcategory for abortion
* Identification (it can be fun to have a surprise movie where some viewers do not see the title upfront)

Start by reviewing the existing MCF category definitions and the nine-comment discussion. Before implementation, the proposed categories, subcategory depth, and sensitive-content scope need a decision; this issue names no files, tests, or entry points, so the implementation target and completion criteria are not yet clear.

Written by the indexing model from the issue text.