Fixes a bug with preview formatting for FAR.
So when we ask the Roslyn API to classify C# for us, it will only
classify the actual C# tokens. We are responsible for filling in the
gaps and whitespace.
The bug is that the following text would have all of its whitespace
removed in the VS FAR preview window.
```
@{ var foo = "Hello, world!"; }
```
Would look like:
```
@{varfoo="Hello, world!";}
```
This fixes the issue and makes it look like what one would expect.
We had a bug where were not returning the correct span for highlighting.
Fixed this.
Also we have a problem here, we're using types in our tests that are
coming from Roslyn - however we're not getting IVT for our test
assemblies. So some additional pain is required.
This change adds mock ups of the interfaces that we've been designing as
part of Razor FAR as well as the implementations. This isn't wired up to
anything yet in this PR, but the basic functionality here is stable
enough for us to stabilize and review.
For now we have the interface definitions in the Razor codebase until a
build of Roslyn is available with these definitions + IVT for us to use
them.
Ryan Nowak