(WIP) Razor engine update.

This reverts commit 1289f612a8d34279add6cffbcdf5eaa1d14c05e4 and updates RazorEngine to version 3.5.0-beta2 (paket doesnt like beta1).
The problem with the previous commit was that upstream projects broke (because of a different dependency).
This time we use the official update of the RazorEngine project.

@forki: I again have a problem with paket. With this change `paket install` will not work:

    Paket failed with:

    Error in resolution.
      Resolved:
        - FAKE 3.12.2
        - RazorEngine 3.5.0-beta2
        - NuGet.CommandLine 2.8.3
        - NUnit 2.6.4
        - NUnit.Runners 2.6.4
        - Microsoft.AspNet.Razor 2.0.30506.0
        - CommandLineParser 1.9.71
        - FSharp.Compiler.Service 0.0.67
      Can't resolve:
        - Microsoft.AspNet.Razor >= 3.0.0
           - from RazorEngine 3.5.0-beta2
     Please try to relax some conditions.

`paket update` worked fine and everything seems to be ok within the project files. Any hint would be very welcome, can we ignore this?
Another thing I noticed: paket seems to add dependencies to the FsLib project files while they do not have any paket.references and they dont need them.

Happy New Year to all who read this :)