Copyedit README, add instructions for running demos
Copyedit README, add instructions for running demos

dart-archive/core-elements,dart-archive/core-elements,orgsea/core-elements,orgsea/core-elements,orgsea/core-elements,ronlobo/core-elements,ronlobo/core-elements,dart-archive/core-elements,ronlobo/core-elements,orgsea/core-elements,dart-archive/core-elements,ronlobo/core-elements