Closes#1413 . Basically, SQLite emits a check in a transaction to see
if it is attempting to write. If the db is in read only mode, it throws
an error, else the statement is executed. Mirroring how Rusqlite does
it, I modified the `OpenFlags` to use bitflags to better configure how
we open our VFS. This modification, will enable us to run tests against
the same database in parallel.
Closes#1433