Better handle data types in SQLite3

[wbyoung]

It would be nice if the SQLite adapter would better handle types as they were written to and read from the database. Types are being automatically transformed by node-sqlite3 when written, but not when read. Specifically, the following would probably be good to map to JS types when reading:

• bool
• time
• date
• datetime
• timestamp
• decimal

If we handle type transformation, we should consider handling the transformations before they're written to the database as well rather than letting node-sqlite3 handle it.

This depends on TryGhost/node-sqlite3#451 being accepted.