* call of non-virtual function in ctor
* use getCopy
* return number of merged models
* change current simulator in model set loader (fixes infinite loop: change data -> signal -> change data).
* adjustments to use deferred caches
* removed simulator from CAircraftModelSetLoader`s signature as it was not used
* only change current simulator when explicitly set (avoid unintended setting)
* added function to obtain number of elements from model caches
* removed from component cache
* kept renamed component caches as stubs for later usage
refs #646, removed gui state cache as it causes build issues on Jenkins
(idea was to keep the classes as stubs for later usage)
* moved caches to blackmisc
* used CModelCaches in loader
* applied changes in simulator specific loader classes
* renamed find function to findFirstByModelStringOrDefault
* made merge function static so it can be used elsewhere