Don't require SAUCE_LABS_ACCESS_KEY env variable when running locally
TEST_OAUTH_PROVIDERS env variable to run only some providers

While at it, remove a test step that's also tested from the password login
tests separately.
Lower default DOM timeout to 200ms

Change all waits that require a server-round trip to
explicitly pass a timeout of 30s. If this works well, we
can have an option `{network: true}` to the wait
functions.
Save screenshot on failure

XXX really should be in a different file, maybe
with an explicit onFailure hook
Print link to Sauce Labs test page before starting test run

This link can be used to see the screencast of tests, which
will in turn help diagnose failures
On Twitter login, click on "Authorize App" if popup asks us to

We need to "Authorize App" on some browsers, but not others. For example,
on my local machine Firefox asks for this, but not Chrome.

Why?
monkey path Email.send and show log on client
more setup for email flow tests
implement test sendEnrollmentEmail method
WIP email flow tests
fix removeTestAccount method name
WIP: remove test account in tests instead of on page load
update email tests to use explicit timeouts for network waits