- Added db:load_extension() function to support SQLite extension libraries.
- Added lversion() function to report library version, e.g., "0.9.3".
- Added some tests for new functions and Lua 5.3 64-bit integers in the database.
- Fixed longstanding bug: if db is no longer live, it is auto-closed by gc, but there may still be live prepared statements. Executing these statements would produce an SQLite error. Prepared statements now hold a reference to the db to prevent it from being collected while the prepared statement is live. Manually closing the db will continue to finalize the statements, as before.