Updated to NuGet 2.7.0.
Using TFS MSBuild's OutDir and GenerateProjectSpecificOutputFolder properties.

During TFS build the OutputPath property is overwritten in MSBuild,
these changes simulates this behaviour for NuBuild.
Add .dll and .exe files to subfolder under lib and tools by target framework version.

Uses remoting to reflection-only-load each .dll into a temporary domain
to be able to unload them. Unload required, because versions of the
assemblies targeting different frameworks usually has the same name.
TODO: Current code works with CLR 4.0 assemblies, because before CLR
4.0, the TargetFrameworkAttribute is not stored in the assembly, we
should parse the .csproj file instead.
Bugfix: Break foreach / return when value has found in NuPrepare.GetPackageID().
RemoteAssembly extended with licence and a general static getter method.

The method encapsulates the remoting steps, only a getter delegate
required.
Replacement tokens also uses RemoteAssembly and ReflectionOnlyLoad.

NuPrepare.GetPackageID() and NuPackage.GetPropertyValue() uses the
separated AppDomain.
New Advanced options: AddBinariesToSubfolder, AddPdbFilesToBinaries