Call function from arduino to app similarly to arduino from app

[Ernest Warzocha]

Latest user issue convinced me to try make it simple.

Now it's possible using interval (recommended) or editing onReceiveParse function in involt.js. I should extend the possibilities. Both hardware and software methods should be similar so user can easily adapt to current situation.

[Ernest Warzocha]

I've made simple hack with calling function in object. User now can add custom function like this:

involtFunctions.test = function(){
console.log("test");
}

and involtSendFunction() in sketch.