Check for compatible framework and dev/platform before build (#71)

Author: ivankravets

library.json

@@ -12,8 +12,11 @@
     "type": "git",
     "url": "https://github.com/me-no-dev/ESPAsyncTCP.git"
   },
-  "version": "1.1.2",
+  "version": "1.1.3",
   "license": "LGPL-3.0",
   "frameworks": "arduino",
-  "platforms": ["espressif8266", "espressif8266_stage"]
+  "platforms": "espressif8266",
+  "build": {
+    "libCompatMode": 2
+  }  
 }