Merge pull request #389 from adrianca88/set_phone_functionality

Added setPhoneFunctionality method

src/TinyGsmClientM590.h

@@ -173,8 +173,7 @@ class TinyGsmM590 : public TinyGsmModem<TinyGsmM590>,
  protected:
   bool restartImpl() {
     if (!testAT()) { return false; }
-    sendAT(GF("+CFUN=15"));
-    if (waitResponse(10000L) != 1) { return false; }
+    if (!setPhoneFunctionality(15)) { return false; }
     // MODEM:STARTUP
     waitResponse(60000L, GF(GSM_NL "+PBREADY" GSM_NL));
     return init();
@@ -190,6 +189,11 @@ class TinyGsmM590 : public TinyGsmModem<TinyGsmM590>,
     return waitResponse() == 1;
   }
 
+  bool setPhoneFunctionalityImpl(uint8_t fun, bool reset = false) {
+    sendAT(GF("+CFUN="), fun, reset ? ",1" : "");
+    return waitResponse(10000L) == 1;
+  }
+
   /*
    * Generic network functions
    */