travis build

different configurations are specified in the configurations directory
 to select one copy it replcing the config.h file (as the travis script does)
 or change the include file directive in crossbow.ino

crossbow/tx_input.h

@@ -0,0 +1,21 @@
+
+#ifndef TX_INPUT_H
+#define TX_INPUT_H
+
+#include "Arduino.h"
+
+#define TX_INPUT_CHANNEL_COUNT 16
+
+class TxInput
+{
+  public:
+  	virtual ~TxInput() {}
+    int get(uint8_t channel) { return channels[channel]; };
+    virtual void start(void) {};
+    virtual void stop(void) {};
+    virtual bool isReceiving(void) { return false; };
+    virtual void loop(void) {};
+    volatile static int16_t channels[TX_INPUT_CHANNEL_COUNT];
+};
+
+#endif