E22 SX1262 module now works!

Thanks mostly to an old github comment by @beegee-tokyo the fix was easy
(comment here https://github.com/jgromes/RadioLib/issues/12#issuecomment-520450429)

We now set DIO3 to 2.4 volts to power the oscillator inside the E22
module (undocumented in the E22 docs)

src/mesh/SX1262Interface.h

@@ -43,6 +43,12 @@ class SX1262Interface : public RadioLibInterface
      * Start waiting to receive a message
      */
     virtual void startReceive();
+
+    /** start an immediate transmit
+     *  We override to turn on transmitter power as needed.
+     */
+    virtual void startSend(MeshPacket *txp);
+
     /**
      * Add SNR data to received messages
      */