First implementation for DeviceMotionEvent

[kersten]

These changes will make your plugin work with devices that have an gyroscope. If you move the device the parallax effect will be visible.

Known bugs:

• The initial position of the layers are not calculated, so there is a white space visible on the left side.
• The demos with the buttons are not working correctly.
• The minified version is nit updated.

I try to finish the bugs in my spare time.

Greetings

[stephband]

This is interesting, thanks for this.

I'm not going to merge it straight away, because:

• It appears to make a choice between using motion events OR mouse events. I think both should be enabled. In fact, I can think of cases where you would want to use parallax without motion events on devices that do have them enabled, so I think motion event support should be an option. (As an aside, I'm working on touch events, and there we definitely don't want an either/or choice).
• Stylistic changes (such as changing all instances of 'jQuery' to '$') are not necessary.

I'm going to study what you've done here and try and implement device motion events as an option. Great idea.

[kersten]

This is ok. I know that styling was not necessary, but my IDE did it by itself, sorry for that.

I want to fix some more stuff tonight, maybe that could be interesting for you too. Eventually I will integrate the option for enabling disabling too.

Greetings