Initial ElementEdge class for position assertions
ElementEdge.diff(): returns empty string when expectation met
ElementEdge has factory methods for all four edges
ElementEdge: common factory code factored out into factoryFn()
Clean up magic numbers in ElementEdge test
IE 8 no longer includes frame border in position calculations
Clarify Frame's workarounds
Roadmap updates
INTEGRATE: ElementEdge performs basic positioning diffs

* dev:
  Roadmap updates
  Clarify Frame's workarounds
  IE 8 no longer includes frame border in position calculations
  Clean up magic numbers in ElementEdge test
  ElementEdge: common factory code factored out into factoryFn()
  ElementEdge has factory methods for all four edges
  ElementEdge.diff(): returns empty string when expectation met
  Initial ElementEdge class for position assertions