[widgets] Dig Sig Spec ready for pub

[Marcos Caceres]

Hi,
I would like to republish the Widgets Dig Sig specification as LC (in 
preparation for moving it to PR):

http://dev.w3.org/2006/waf/widgets-digsig/

I have also recreated the test suite to match the new specification:

http://dev.w3.org/2006/waf/widgets-digsig/test-suite/

Kind regards,
Marcos