Several changes in the UI

More progress towards completion of issues #22 & #25 (help descriptions for rules and reproduce documentation):

* Added W3C logo.
* Added link to project and source code.
* Changing layout of page (options more compact, summary of results).
* Result summary and progress bar hidden initially.
* Changed text on progress bar.
* Layout of inputs more compact.
* Fixed handling of new "processDocument" parameter.
* Minor design & CSS improvements.
* First field on form now gets user focus automatically.