Deals with a special topic: While frequencies at VATSIM/flightsim are usually set in 25kHz spacing, some ATC stations (radar) require 8.33kHz tuning.
The now made extension handles this and allows to listen to a voice room even if the corresponding frequency is not exactly tuned in.
Example: EKDK_CTR 135,270 but needs to be tuned in as 135,275
* rename CStatusMessages to CStatusMessageList
* rename NetworkVatlib to CNetworkVatlib
* replace all occurrences of Realname with RealName (correct camel case)
* CSequence method corresponding to CList::append is push_back
* don't compile the qdbuscpp2xml metadata plugin by default
* CAircraftIcao string members always trimmed and capitalized
* added CComSystem::roundTo25KHz
* using epsilon comparison in a couple of places
refs #81
