Add Native support to NuGet dependencies

[DinisCruz]

The idea is to add a similar tag to O2Ref: where one can put references to Nuget packages using for example `NuGet:Newtonsoft.Json``

This would call nuget.exe and install (if needed) that package into a specific temp _NuGet folder.

A reference to all dlls inside that installed NuGet package also needs to be added to the list of Referenced assemblies

[DinisCruz]

The first pass of this feature has been added to 5.5 RC0

[DinisCruz]

this is now working