Override default compat mode in PlatformIO manifest

Please consider merging this PR since the default compatibility mode is `soft` that prohibits compilation of this library if no `framework` field is specified in `platformio.ini` file (which is the default choice for `native` platform). 
Thanks!

Author: valeros

library.json

@@ -14,6 +14,9 @@
   "exclude": [
     "test"
   ],
+  "build": {
+    "libCompatMode": "off"
+  },
   "frameworks": "arduino",
   "platforms": "native"
-}
+}