Added default constructor

PubSubClient.cpp

@@ -13,6 +13,9 @@
 #define MQTTPUBLISH 3<<4
 #define MQTTSUBSCRIBE 8<<4
 
+PubSubClient::PubSubClient() : _client(0) {
+}
+
 PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, void (*callback)(char*,uint8_t*,int)) : _client(ip,port) {
    this->callback = callback;
 }

PubSubClient.h

@@ -25,6 +25,7 @@ private:
    int write(uint8_t header, uint8_t* buf, uint8_t length);
    uint8_t writeString(char* string, uint8_t* buf, uint8_t pos);
 public:
+   PubSubClient();
    PubSubClient(uint8_t *, uint16_t, void(*)(char*,uint8_t*,int));
    int connect(char *);
    int connect(char*, char*, uint8_t, uint8_t, char*);