Testing external clock detection and auto-switch

Simplified audio spectrum computation and transfer
ACARS RX in debug mode
Disabled ABI warnings
Updated binary

firmware/application/portapack.hpp

@@ -59,6 +59,9 @@ extern TemperatureLogger temperature_logger;
 void set_antenna_bias(const bool v);
 bool get_antenna_bias();
 
+void poll_ext_clock();
+bool get_ext_clock();
+
 bool init();
 void shutdown();