RoboVM module

Hi,

I have continued the work started by @thypon in https://github.com/libgdx/libgdx-maven-archetype/pull/9 and quite finished it.

I've updated the version to 1.0-SNAPSHOT (as there is no more 0.9.9-SNAPSHOT jars in maven repositories).

Xamarin.iOS related files have been removed.

Native iOS library are correctly unpacked, same stuff as in the android module, and referenced in the `robovm-maven-plugin` configuration.

I'm quite not sure about the frameworks but I've put the same ones I found in the superjumper demo:

    <frameworks>
        <framework>UIKit</framework>
        <framework>OpenGLES</framework>
        <framework>QuartzCore</framework>
        <framework>CoreGraphics</framework>
        <framework>OpenAL</framework>
        <framework>AudioToolbox</framework>
        <framework>AVFoundation</framework>
    </frameworks>

Tested by running 

    mvn robovm:iphone-sim

 in the ios maven module (after installing the core module of course).