Introduce getJobSetDisplayName

Let's add the getJobSetDisplayName method to the JobSet class.
It returns the localized name (so that you don't have to call tc()) and it
optionally escapes the name in html format, javascript format (default is
to escape in html format).
Remove the json encoding option from getJobSetDisplayName
Merge pull request #1446 from mlocati/add-JobSetDisplayName

Introduce getJobSetDisplayName