Dev db refactor

Refactored the DB class to make (my) life easier. I needed to access some of the PDO class' functions and couldn't without adding wrapper functions. For the functions I needed this was overkill as they would be used direct, no new logic needed, so I refactored to allow the class to return the PDO object while maintaining the shared use of it.
In the process of using other methods I found they were only partially complete, so I have added what I thought was needed to bring them up to the intended functionality. See queryAssoc() as an example. There are still a number of methods that do not seem complete, or will not funtion as the comments/names would imply. I can work on them also if needed/wanted.