Added features, working from original class.

Added and modified the following:

$db->groupBy('value') 	// adds GROUP BY to query. Use as many times in the query as you like. Note: with groupBy, you may need to use $db->rawQuery if the query is super complicated, because $db->get('tablename') returns all fields. Use as many as you like in a construct.
		
$db->getResultRows() // returns number of rows in SELECT, and number of rows affected in UDPATE, INSERT, DELETE.

$db->where('u_username', '>', 'test1') 	// (field, test operator, value). 
										//The original class did not have the test operator. Use as many as you like in a construct.

$db->orderBy('testkey', 'desc') // use as many as you like in a construct									
$db->getQueryStructure() // displays the prepared query itself that is sent to the server. Good for debugging.