created DatabaseManager class, GTblVal class, and Log class.  DatabaseManager was made to handle the application's database.  GTblVal is a class for Global Table Values such as table names and column names. The Log class was created as a wrapper to the android.util.Log class that makes it easier to code log messages as well as view them on the logcat. Added code to MainActivity to test/debug databasemanager. Also modified the manifest to enable debugging on devices.