Remove dangling whitespace & formatting.
Add a method to deleteEntities given a list.

Call this method with list of instances that implement the interface
BaseModelInterface and all instances will be removed from the database.
Add methods for retrieval using string comparison.

These methods will return List<EntityClass> using string comparisons.
Use more specific argument type declaration.

Thanks to @chrismayer for the suggestion. This also removes the
rather ugly-looking `BaseModelInterface.class.isAssignableFrom(clazz)`
and the type cast afterwards.
Be more explicit about return type of new methods.
Merge pull request #28 from marcjansen/more-dbdao-methods

More DatabaseDAO methods