Supporting yarn and npm workspaces

[codeinabox]

It would be handy to support yarn and npm workspaces, initial support could be to check for the presence of workspaces in the root package.json and when calling TestSuite it would yarn workspaces run test.

When it comes to testing files the root package.json could also be parsed to determine the package.json of the workspace, which would improve mono repo support.

Feel free to add any more thoughts or suggestions to this