Add FSharp.Core assembly redirect
In some contexts the assembly redirect is necessary and a bit difficult to
debug if it it isn't there.
Merge pull request #110 from dcharbon/add_assembly_redirect

Add FSharp.Core assembly redirect
Assembly reference fixes
Don't reference a specific version of FSharp.Core for FSharp.Server.exe
and fix probing locations path so that it expects to be in a packages
directory.