Further reduce dependencies for cross-platform
Further reduce dependencies for cross-platform

We don't actually need these references in the core now. The code that
needed them has been moved out into .fsx e.g FSharp.Charting.fsx

fradav/IfSharp,BayardRock/IfSharp,npmurphy/IfSharp,BayardRock/IfSharp,npmurphy/IfSharp,BayardRock/IfSharp,fradav/IfSharp,npmurphy/IfSharp,fradav/IfSharp,npmurphy/IfSharp,fradav/IfSharp,BayardRock/IfSharp