add dependency compile time version check

Author: toddtreece

AdafruitIO.cpp

@@ -1,6 +1,15 @@
 #include "AdafruitIO.h"
 
-AdafruitIO::AdafruitIO(){}
+AdafruitIO::AdafruitIO()
+{
+  _mqtt = 0;
+  _username = 0;
+  _key = 0;
+  _err_topic = 0;
+  _throttle_topic = 0;
+  _err_sub = 0;
+  _throttle_sub = 0;
+}
 
 void AdafruitIO::connect(const char *user, const char *key)
 {

AdafruitIO.h

@@ -7,12 +7,21 @@
 #include "AdafruitIO_Feed.h"
 #include "AdafruitIO_Data.h"
 
+#ifndef ADAFRUIT_MQTT_VERSION_MAJOR
+  #error "This sketch requires Adafruit MQTT Library v0.15.0 or higher. Please install or upgrade using the Library Manager."
+#endif
+
+#if ADAFRUIT_MQTT_VERSION_MAJOR == 0 && ADAFRUIT_MQTT_VERSION_MINOR < 15
+  #error "This sketch requires Adafruit MQTT Library v0.15.0 or higher. Please install or upgrade using the Library Manager."
+#endif
+
 class AdafruitIO {
 
   friend class AdafruitIO_Feed;
 
   public:
     AdafruitIO();
+    ~AdafruitIO();
 
     void connect(const char *user, const char *key);
     void connect(const __FlashStringHelper *user, const __FlashStringHelper *key);

AdafruitIO_Definitions.h

@@ -1,7 +1,7 @@
 #ifndef ADAFRUITIO_DEFINITIONS_H_
 #define ADAFRUITIO_DEFINITIONS_H_
 
-#define ADAFRUITIO_VERSION_MAJOR 1
+#define ADAFRUITIO_VERSION_MAJOR 2
 #define ADAFRUITIO_VERSION_MINOR 0
 #define ADAFRUITIO_VERSION_PATCH 0
 

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit IO Arduino
-version=1.0.1
+version=2.0.0
 author=Adafruit
 maintainer=Adafruit <[email protected]>
 sentence=Arduino library to access the Adafruit IO REST API.