Tokens are similar to sessions in that they stand in for users, but the
protocol handlers will manage them; Fever login hashes are the
originating use case for them. These must never expire, for example,
and we need to specify their values.
This commit also performs a bit of database clean-up
This involved changes to the driver interface as well as the database
schemata. The most significantly altered queries were for article
selection and marking, which relied upon unusual features of SQLite.
Overall query efficiency should not be adversely affected (it may have
even imprved) in the common case, while very rare cases (not presently
triggered by any REST handlers) require more queries.
One notable benefit of these changes is that functions which query
articles can now have complete control over which columns are returned.
This has not, however, been implemented yet: symbolic column groups are
still used for now.
Note that PostgreSQL still fails many tests, but the test suite runs to
completion. Note also that one line of the Database class is not
covered; later changes will eventually make it easier to cover the line
in question.
