Add support for TS3.0 projectReferences

[rbuckton]

Adds support for building projects using TS 3.0 project references.

[rbuckton]

@ivogabe Can you take a look? Unfortunately, TypeScript itself can no longer use gulp-typescript in 'master' until minimal project reference support is added.

[rbuckton]

Not certain what's causing the test failure, as it is passing on my machine.

[ivogabe]

Thanks for the PR, will take a look at it this weekend. I’ll also look at the test failure.

[ivogabe]

When I run the tests, I get the following diff with your baselines: 53823ab. The CI probably has the same errors, I'm not sure why it doesn't show that in the output though. Is that baseline correct? Or is this not intended?

Other than that, the changes are good and can be merged.

[ivogabe]

(Could the difference in output for the test be caused by Windows versus Linux/Mac?)

[rbuckton]

@ivogabe I found the issue and updated the PR.

[ivogabe]

Thanks for the PR, released as 5.0.0-alpha.2