Introduced ViewerException and ParseException and started switching to them.
Added stylesheet methods to Works, Work, Edition.
Renamed Selection/SelectionResource.
Split out ContentResource.
Added FontsResource.
Added media types to the GETs.
All stubs moved from webapp to viewer.
Introduced Editions.editions.
Html adds URIs of all existing stylesheets (for content).

--HG--
rename : webapp/src/main/scala/org/podval/judaica/webapp/StructureSelectionResource.scala => webapp/src/main/scala/org/podval/judaica/webapp/DivSelectionResource.scala
rename : webapp/src/main/scala/org/podval/judaica/webapp/ContentSelectionResource.scala => webapp/src/main/scala/org/podval/judaica/webapp/StructureSelectionResource.scala