Well, this is embarassing. Somehow the freelist was never getting written after each commit.
This commit fixes that and fixes a small reporting issue with "bolt pages".
I consolidated the DB.Tx() and DB.RWTx() calls into a single
DB.Begin(writable bool) call. This is more consistent with the
database/sql library.
I also changed the DB.Do() and DB.With() call to DB.Update() and
DB.View(), respectively. This is more intuitive and more inline with
other database verbiage.