TCAS Resolution Advisory only for v2

FTC=28 subcode=2 was handled as TCASResolutionAdvisoryMsg, yet this is only valid for V2 targets.

For V0 and V1 targets, this format combination is undefined and should rather return the ExtendedSquitter.

Fixes #42

Author: fixje

src/main/java/de/serosystems/lib1090/StatefulModeSDecoder.java

@@ -173,9 +173,9 @@ public ModeSDownlinkMsg decode(ModeSDownlinkMsg modes, long timestamp) throws Ba
 					if (ftc == 28) { // aircraft status message, check subtype
 						int subtype = es1090.getMessage()[0] & 0x7;
 
-						if (subtype == 1) // emergency/priority status
+						if (subtype == 1)
 							return new EmergencyOrPriorityStatusMsg(es1090);
-						if (subtype == 2) // TCAS resolution advisory report
+						if (subtype == 2 && dd.adsbVersion > 1)
 							return new TCASResolutionAdvisoryMsg(es1090);
 					}