* prepared for login/off sounds
* prepared for text message sounds
* helper method to play sounds
* enabled mute / mixer also in cockpit, including context menus
* settings for notification sounds
* some minor tweaks, e.g. changed signal/slot to C++ style where missing
* added methods to get results in context
* added signal to indicate audio test completed
* updated GUI to display results
* changed test run methods to non-const to be consistent with voice lib
* Logic in GUI to avoid parallel / interfering tests
* Fixed wrong Q_ASSERT message and QTimer::singleShot in voice_vatlib.cpp
Changed back signal/slot connection to old style
The described problem is one of the disadvantages of the new style,
when it comes to default values or different signatures
Also using a minimum value and adjusting the slider to any set value.
* 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