Loading `db/sqlite3' no longer raises an exception if
the SQLite library isn't found. Instead, `sqlite3-connect'
raises an exception, while `sqlite3-available?' reports
whether it will work.
The dynamic test allows the documentation-help system
to continue to work if SQLite3 is not available. Currently,
though, `raco setup' still insists on using SQLite3 to
build the database of documented tags.
In some cases, statements were disappearing from statement-table
without being finalized; this makes disconnect fail.
(I was only able to produce the problem when the db lib was
instantiated in a sub custodian that is later shutdown....
like the way the rackunit gui runs the test suite.)
