adding order by functionality

Hi Martin/Brandon,

As promised here is the order by functionality added.

It shouldn't break anything you have already as it's ignored if you don't supply an order by field as you can see, it's pretty fool proof to use.

I've tested it with my project using a live CloudSearch domain and it's working well, I just do:

SearchQuery<SearchType> searchQuery = new SearchQuery<SearchType> { BooleanQuery = query, Facets = facets ... OrderByField = "whatever_you_like", OrderByAsc = true/false};

Hopefully you'll be able to accept this into the main project and eventually it'll make it back onto NuGet.  I've removed the NuGet reference in my project for now to use this version but once it becomes available I'll start using the NuGet version again for sure.

Cheers for the help yesterday too by the way.

Thanks,

Raymond