bytea compatibility fix, tests, and error handling fixes
This prevents warnings on PostgreSQL < 9.1 when PQescapeByteaConn produces escape sequences. This involved moving execute_ and its dependencies into Internal. Sorry.
I really should start writing a test suite
See commit cd76bea
Conflicts: src/Database/PostgreSQL/Simple.hs src/Database/PostgreSQL/Simple/FromField.hs src/Database/PostgreSQL/Simple/QueryResults.hs
Use exception mask in withTransactionMode, and compile with -Wall
The concerns detailed in 5f045cc should now be taken care of by the revised interface. Namely, the Ok constructor must be forced in order to determine whether or not an exception is thrown, and the Ok constructor evaluates it's argument to whnf.
It turns out that by default, "BEGIN" usually means the same as "BEGIN ISOLATION LEVEL READ COMMITTED", but this isn't necessarily so.