Merge pull request #70 from ivankravets/patch-1

Declare header files for PlatformIO

library.json

@@ -22,5 +22,6 @@
   ],
   "version": "1.5.6",
   "frameworks": ["arduino","mbed","espidf"],
-  "platforms": "*"
+  "platforms": "*",
+  "headers": "arduinoFFT.h"
 }