Minor preparations for getRevision
Minor preparations for getRevision

- include the 'hidden' field in the DB schema with which we can track if
  some aspects of the revision should not be exposed
- modify fetchAndStoreMWRevision() to allow it to serve both
  getTitleRevision() and getRevision()

d00rman/restbase,physikerwelt/restbase,milimetric/restbase,Krenair/restbase,wikimedia/restbase,Krenair/restbase,cscott/restbase,inverno/restbase,inverno/restbase,physikerwelt/restbase,Pchelolo/restbase,gwicke/restbase,wikimedia/restbase,wikimedia/hyperswitch,eevans/restbase,cscott/restbase,wikimedia/mediawiki-services-restbase,d00rman/restbase,wikimedia/mediawiki-services-restbase,milimetric/restbase,eevans/restbase,gwicke/restbase,Pchelolo/restbase