MBS-4962: set aggressive expires headers for 10 after the hour on requests to slave servers that won't update more frequently
MBS-4962: set Last-Modified too
MBS-6179: don't include null catalog numbers in the sort key when sorting by catalog number
MBS-6263: don't show blank values in Create Area edits
Merge branch 'master' into mbs-6179

Conflicts:
	lib/MusicBrainz/Server/Data/Release.pm
MBS-6179: basic back to functioning for collection sorting
MBS-6179: fix up my faulty miscopy
remove  entirely
Remove duplication of knockout.js include between relationship-editor and knockout manifests.
MBS-6409: don't translate ModBot edit note for URLs already having been merged
Merge branch 'mbs-6263-area-edit-display' into beta

* mbs-6263-area-edit-display:
  MBS-6263: don't show blank values in Create Area edits
Merge branch 'fixup-ko' into beta

* fixup-ko:
  Remove duplication of knockout.js include between relationship-editor and knockout manifests.
Merge branch 'mbs-6409' into beta

* mbs-6409:
  MBS-6409: don't translate ModBot edit note for URLs already having been merged
Merge branch 'mbs-4962' into beta

* mbs-4962:
  MBS-4962: set Last-Modified too
  MBS-4962: set aggressive expires headers for 10 after the hour on requests to slave servers that won't update more frequently
Merge branch 'mbs-6179' into beta

* mbs-6179:
  remove  entirely
  MBS-6179: fix up my faulty miscopy
  MBS-6179: basic back to functioning for collection sorting
  MBS-6179: don't include null catalog numbers in the sort key when sorting by catalog number