Update FSC to 0.0.43.

There are a lot of bug fixes in FSC since 0.0.36. This commit doesn't begin to take advantage of the new async methods in FSC, but puts us in a better place to begin improving responsiveness.
Merge pull request #443 from rojepp/fsc0.0.43

Update FSC to 0.0.43.
Merge pull request #444 from fsharp/master

merge changes from master