POC: Implement multiple unsaved file checking

[rojepp]

I'm sure this can be improved, but it seems to work.
Sorry about the diff containing a lot of non-change lines. I tried using Atom for this. :)
Basic idea is, keep a mutable version of State. This can be queried by IFileSystem at any time.
This means F# compiler sees changes as fact. Fixes #6

[rojepp]

On my machine I got diffs when running integration tests because FSharp.Core is missing. Not sure if it is on my machine only.

[rneatherway]

Hmm, that diff sounds a bit annoying. Is that in the list of project references returned? And you are running OS X? I'm a bit surprised because the test project files do contain an explicit reference. This doesn't affect merging this PR, but could you post the diff?

Would you also mind adding a new test for this? It should be fairly easy to just copy Test1 and change the parse calls near the top to send some different contents.

[rojepp]

Sure, I'll add tests for it within a few days. And post the diffs probably tonight.

[rojepp]

Before:

{"Kind":"project","Data":{"Project":"/test/integration/ErrorTestsJson/Test1.fsproj","Files":["/test/integration/ErrorTestsJson/FileTwo.fs","/test/integration/ErrorTestsJson/Program.fs"],"Output":"/test/integration/ErrorTestsJson/bin/Debug/Test1.exe","References":["/FSharp.Core.dll","/System.Core.dll","/System.dll","/mscorlib.dll"],"Framework":"v4.0"}}

After:

{"Kind":"project","Data":{"Project":"/test/integration/ErrorTestsJson/Test1.fsproj","Files":["/test/integration/ErrorTestsJson/FileTwo.fs","/test/integration/ErrorTestsJson/Program.fs"],"Output":"/test/integration/ErrorTestsJson/bin/Debug/Test1.exe","References":["/System.Core.dll","/System.dll","/mscorlib.dll","/FSharp.Core.dll"],"Framework":"v4.0"}}

FSharp.Core is the only thing that differs. Note, the same diffs occur for me on master, without this PR. I'm on OSX.

[rneatherway]

Works nicely in Emacs, thanks!

The thing with the FSharp.Core looks like the references are not being output in the same order. I sort them to try to avoid this, but I guess the earlier parts of the path are different on OSX. Could you try changing that line to:

References = List.sortBy Path.GetFileName p.References

That might do the trick.

[rneatherway]

And released! https://github.com/fsharp/FSharp.AutoComplete/releases/tag/0.16.0