Move waitForRequest outside testcase

This allows it to be used in multiple test cases
Test that the polling mechanism works for a single interval
Implement stop to clear the polling timeout
Add poll function that calls start on poller object
Set url property on poller object
Add properties on poller passed via options
Use tddjs.extend instead of loop to copy attributes
Add placeholder for Date constructor stub
Enable stubbing of Date to return same object twice
Alternate date implementations between calls to constructor

At least once.
Improve testing semantics through name changes