* split JsonDatastoreResponse in subclass HeaderResponse
* support for request newtwork request duration ("started") in application
* removed ps_setupChanged because it was unused
* added amit functions in readers
* cacheHasChanged functions (needed because data of caches are loaded in background)
* pinned small caches
* CDatabaseReader::readInBackgroundThread uses admitCaches now
* do not init shared URLs before needed
* do not load info objects when DB is unavailable
* adjust reader flags when DB is down
* airport URL available in setup
(applied after 1st performance fix for cache was ready)
* utility functions to detect if only caches are used
* renamed some functions
* renamed some db flags and added new ones
* 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