Resolve the SQLite 'bug' concerning NUL characters in TEXT.

The sqlite3 module (PySqlite2) maps Pythons str type to SQLites TEXT data type.
However for performance reasons SQLite assumes, in some cases, that TEXT data
is NUL terminated resulting in truncated strings. Binary data can be reliably
stored and retrieved using Pythons buffer type and SQLites BLOB type, which
PySqlite2 automatically maps together.