add new tagIDs parameter to tagme() that builds a database for specific tags only

[jbrzusto]

from @tabanid:
It would be nice to be able to grab detections for a set of tags without pulling in all tags from the project(s).

One approach is to augment the calling conventions for tagme, adding a parameter
tagIDs, a vector of integer motusTagIDs. The resulting database would look like a tag project DB,
but include data only for a specific set of tags. Ideally, that set could be augmented from one call
of tagme() to the next. The meta table for that DB could indicate that it's a tagset DB, and
list the corresponding tag IDs.