Fix for mac project not producing the correct constructors

As reported [here](http://forums.xamarin.com/discussion/comment/88444#Comment_88444)

The fix is to switch to the FSharpCleanCodeProvider, this was previously not possible due to a bug in [monodevelop](https://github.com/mono/monodevelop/commit/ca089a970c0c64ac5d7e73d0f5296ca13d5e0087)