Lgm_QinDenton: added persistence attribute and recall option for Q-D
Lgm_QinDenton: include Dst and Kp in persistence
Lgm_QinDenton: corrected labelling of persistence data in Q-D print (verbose setting)
lgmpy:tests: updates to the tests and pulled some common code into a utils file
lgmpy:tests: more fixus and get the overall tests working
Fixed return of null from non-void functions (now cast NULL to return type)