Add inline method documentation for PromisedWebDriver.
Update dojo2-core dependency. Fixes #59.
Add information for end-users to contributing guidelines

since they are linked from the new issue page.
Exit gracefully

This enables reporters to perform additional asynchronous actions
at the end of their tests without being forcibly aborted by Intern
trying to exit the process prematurely.
Fix style violation
Merge branch 'master' into geezer

Conflicts:
	package.json