SQLite optimizations. (addressing #34)

- Added indexes.
- Only call OsuDB.insert() if necessary.
- Drop/recreate indexes for batch inserts.
- Added pragmas for "locking_mode" and "journal_mode".

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/db/ScoreDB.java

@@ -114,7 +114,8 @@ public class ScoreDB {
 					"combo INTEGER, " +
 					"perfect BOOLEAN, " +
 					"mods INTEGER" +
-				")";
+				");" +
+				"CREATE INDEX IF NOT EXISTS idx ON scores (MID, MSID, title, artist, creator, version);";
 			stmt.executeUpdate(sql);
 		} catch (SQLException e) {
 			ErrorHandler.error("Could not create score database.", e, true);