Fix #3, Fix #2

TinyGsmClientM590.h

@@ -253,6 +253,54 @@ public:
     return res;
   }
 
+  String getIMEI() {
+    sendAT(GF("+GSN"));
+    if (waitResponse(GF(GSM_NL)) != 1) {
+      return "";
+    }
+    String res = stream.readStringUntil('\n');
+    waitResponse();
+    res.trim();
+    return res;
+  }
+
+  int getSignalQuality() {
+    sendAT(GF("+CSQ"));
+    if (waitResponse(GF(GSM_NL "+CSQ:")) != 1) {
+      return 99;
+    }
+    int res = stream.readStringUntil(',').toInt();
+    waitResponse();
+    return res;
+  }
+
+  bool callAnswer() {
+    sendAT(GF("A"));
+    return waitResponse() == 1;
+  }
+
+  bool callNumber(const String& number) {
+    sendAT(GF("D"), number);
+    return waitResponse() == 1;
+  }
+
+  bool callHangup(const String& number) {
+    sendAT(GF("H"), number);
+    return waitResponse() == 1;
+  }
+
+  bool sendSMS(const String& number, const String& text) {
+    sendAT(GF("+CMGF=1"));
+    waitResponse();
+    sendAT(GF("+CMGS=\""), number, GF("\""));
+    if (waitResponse(GF(">")) != 1) {
+      return false;
+    }
+    stream.print(text);
+    stream.write((char)0x1A);
+    return waitResponse(60000L) == 1;
+  }
+
   SimStatus getSimStatus(unsigned long timeout = 10000L) {
     for (unsigned long start = millis(); millis() - start < timeout; ) {
       sendAT(GF("+CPIN?"));