Type: File handling

[baronfel]

reworked version of the old pr which addresses #60.

I kept the webapi endpoints because they worked just fine, and reworked a bit how we'd actually handle/represent the file streams.

Doing most of the work was much easier thanks to the MultiPartFormContent type.

My pain right now is what you should see during the test failures:

unknown expression
  TryFinally (WhileLoop (Call (Some (enumerator), MoveNext, []),
    Let (forLoopVar,
      Call (Some (enumerator), get_Current, []),
        Let (name,
          Call (Some (forLoopVar), get_Item1, []),
            Let (data,
              Call (Some (forLoopVar), get_Item2, []),
                Call (Some (content), Add,
                  [Coerce (NewObject (StreamContent, data), HttpContent), name, name]))))),
                    IfThenElse (TypeTest (IDisposable, Coerce (enumerator, Object)),
                      Call (Some (Call (None, UnboxGeneric, [Coerce (enumerator, Object)])), Dispose, []),
                        Value (<null>)))

So my guess is that I'm somehow messing up the iteration on line 208 where we'd add file parts to the overall multipart content.

Thoughts?

[sergey-tihon]

@baronfel Please try to replace for loop by Seq.iter - fsprojects/FSharp.TypeProviders.SDK#206

[sergey-tihon]

Closed in favor of #131