Add support for prepared statement flags

[EvanBalster]

The SQLite::Statement constructor does not support the prepFlags argument to sqlite3_prepare_v3.

Prepare Flags 🗎 have a few nifty uses:

• SQLITE_PREPARE_PERSISTENT hints that we'll retain and reuse the statement many times.
• SQLITE_PREPARE_DONT_LOG is useful for testing SQL syntax such as in live-coding environments.