Add link to test-suite to demo page.
Removed unimplemented tests.
Minor selection API refactor as a preparation for a switch to different Range model.

At the moment, ranges use the general addressing (property path + charPos).
However, this is not useful as an internal representation
(e.g., not easy to determine the order of addresses), where it is better
to have (compPos, charPos).
The general addressing scheme will be used as an API interface.
Shifted node factory method to DocumentSchema API.

Plus: provides Container with ComponentFactory.
Add helper for creating dm.Range instances to dm.Surface.
Fix in browser impementation for loadHTML.
Made json test fixtures js files.
Consider hash for running single test suite.
Added SurfaceTest.
Not a real change.