Merge pull request #389 from adrianca88/set_phone_functionality

Added setPhoneFunctionality method

src/TinyGsmClientA6.h

@@ -191,6 +191,8 @@ class TinyGsmA6 : public TinyGsmModem<TinyGsmA6>,
 
   bool sleepEnableImpl(bool enable = true) TINY_GSM_ATTR_NOT_AVAILABLE;
 
+  bool setPhoneFunctionalityImpl(uint8_t fun, bool reset = false) TINY_GSM_ATTR_NOT_IMPLEMENTED;
+
   /*
    * Generic network functions
    */