Bug: Click event firing even when button was held

A button click event should only be fired when the button was not held.

In Button.cpp

``` C++
if (cb_onClick) {
  cb_onClick(*this);
} //fire the onClick event AFTER the onRelease
```

should be

``` C++
if (!triggeredHoldEvent && cb_onClick) {
  cb_onClick(*this);
} //fire the onClick event AFTER the onRelease
```
