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
Releasing new candidate 0.5.17