Added Keyword Model,responsible for getting/creating/deleting keywords

* Abstracts a lot of the code away from the Model class.
vendor stuff
Heavy Refactor of the Media Model, follows conventions,uses created_at

* Populates the "created_at" field automatically in mySQL
* Follows convention of creation/saving
  * Hand-written queries
* Uses Keyword model to handle keyword stuff.
* Upload form now prints error messages.