Bugfixes: NullPointerExceptions & Sort on property

App: SessionFactoryImplementation hasn't been initialized
ChemistryContext: clear() called on children, which was null
SimplePropertyManager: Sorting the Properties of a CMISObject
  has been done on immutable List. Fixed by using a LinkedList.
Removed sorting of cmis properties

From now on, the properties of a CMIS Object will be printed
out as they will provided by the OpenCMIS API.
Added shutdown message if program is killed
Added simple slf4j logger as dependency