This is a prerequisite to issue 89 (adding support for .NET 4.5 and SL5).
We'll need to:
1) Upgrade the solution and projects
2) Address any F# 3.0 breaking changes
3) Drop the SL4 projects (which are no longer supported; we will replace with
SL5 support, see issue 89)
4) Adapt the build scripts (perhaps taking the opportunity to move away from
.bat scripts, see issue 74)