Update Widget API names and parameter names

banner -> bannerForPub
resource -> dataPackageForPub

Parameters are now referrer and pubId
Updates to Widget API java code

Handle DOIs in http://dx.doi.org/... format
Rename parameters to be consistent with cocoon
Generate 404 page when no data package found

WidgetBannerAction throws ResourceNotFoundException when not found
widgets.xmap handles errors and generates 404 page
Fix search query for lookup - prevent false 404s

Was requiring dc.type.embargo to be none.  So any item without dc.type.embargo was unavailable.  Remove dc.type.embargo from query and simply check if it exists in the result
Merge pull request #226 from datadryad/trello-13

Updates for Widget API