Unexport buttons on uncaught exception

lib/intval/index.js

@@ -43,6 +43,9 @@ class Intval {
 			}
 		}
 		this._declarePins()
+		process.on('SIGINT', () => {
+			this._undeclarePins()
+		})
 	}
 	_declarePins () {
 		this._pin.fwd = Gpio(4, 'out')
@@ -52,6 +55,12 @@ class Intval {
 
 		this._pin.release.watch(this._watchRelease)
 	}
+	_undeclarePins () {
+		this._pin.fwd.unexport()
+		this._pin.bwd.unexport()
+		this._pin.micro.unexport()
+		this._pin.release.unexport()
+	}
  	_startFwd () {
 		this._pin.fwd.set(1)
 		this._pin.bwd.set(0)