Updates sinon-chai definition and tests to support loading sinon-chai as a
chai plugin.

- usage is as follows:
    import sinonChai = require('sinon-chai');
    chai.use(sinonChai);
- Also updates the tests to compile with --noImplicitAny
Merge pull request #2897 from cspotcode/master

Updates sinon-chai definition and tests to support loading sinon-chai as a chai plugin.