previewer: embedded record display

[tiborsimko]

In addition to porting two standalone previewers (#1318, #1319), we also need to make sure to port the embedded previewers, so that events are nicely displayed directly inside the detailed record pages such as http://opendata.cern.ch/record/631. For CMS events, this functionality exists in COD2 and should be ported to COD3. For OPERA events, this functionality does not exist in COD2 but could/should be added to COD3 for the extra ease-of-use it would bring.

[tiborsimko]

It works now, here is an example:

• http://opendata-qa.web.cern.ch/record/631

Closing the issue.