Plugin fallback for 2.X and 3.X version of phonegap

I have installed (`phonegap plugin add com.phonegap.plugins.mapkit`) your plugin with phonegap `3.4.0-0.19.7` and couldn't make it work properly. I have found a fix in the following link and integrated it in your code.
[Phonegap issue](https://github.com/phonegap-build/GAPlugin/pull/37)

Let me know what you think.