Sometimes you only want to read. This adds a readonly flag to the SqliteDb constructor and open() function.
shortens long line.
adds close for cleanup where sqlite3_open may have returned an error. Caught by @gidden
changes 0 to NULL for compatibility with google style guide
Merge pull request #470 from katyhuff/sqlite_readonly

Adds a readonly option to the SqliteDb, adds close statement if open fails as required by the sqlite3 documentation, and changes uses of 0 to NULL as per the google style guide.