#175 added delete method for Algorithms
#175 added test for delete call on unstored Algorithms
#175 implemented delete on DatabaseConnection.java
#175 pulled store and delete methods to abstract class
store method is abstract
in algorithm retrieveAll uses criteria
#175 made DatabaseConnection.java extend ResultsDbEntity
removed duplicate tests in AlgorithmTest.java and DatabaseConnectionTest.java
#175 made Execution extend ResultsDbEntity
#175 made Inputs extend ResultsDbEntity
fixes #175 made Result extend ResultsDbEntity