Added timeout to read

(cherry picked from commit 29dd7fd472)

src/TinyGsmClientESP8266.h

@@ -133,7 +133,8 @@ public:
   virtual int read(uint8_t *buf, size_t size) {
     TINY_GSM_YIELD();
     size_t cnt = 0;
-    while (cnt < size) {
+    uint32_t _startMillis = millis();
+    while (cnt < size && millis() - _startMillis < _timeout) {
       size_t chunk = TinyGsmMin(size-cnt, rx.size());
       if (chunk > 0) {
         rx.get(buf, chunk);