Refactoring owlapi adaptor

[alkidbaci]

• Fixed bug where JVM was never shutting down because of an always false check.
• Removed __enter__ and __exit__ methods from OWLAPIAdaptor because that structure does not allow for creation of new instance of OWLAPIAdaptor. That is because if the JVM is stopped then you cannot restart it ( this is a limitation of JPype)
• Currently when initializing an object of OWLAPIAdaptor the JVM is started automatically (this is required to perform the successful initialization of the object, therefore the option to manually start the JVM is not possible)
• New method: To stop the JVM the user can use the method OWLAPIAdaptor.stopJVM(). This method can be called when the user is finished with using its adaptor objects.
• Updated examples and documentation in accordance
• Version update for the new release