Manual avionics & airframe: Fixed wrong ref. to device config.
Util/StringUtil: Add StringStartsWithIgnoreCase function
Airspace/AirspaceParser: Relax parsing of TNP airspace files

Fixes trac issue #3272.
Merge remote-tracking branches 'hjr/v6.7.x' and 'apf/v6.7.x' into v6.7.x