Drop 0.90 compatibility

No need for funky 1.0 backwards compatibility stuff with script fields.
Replaced with _source filtering which is way easier to work with.

Elastica upgrade required a few changed because it made the settings results
simpler.

Change-Id: I08e1c2f30d11cab0495e7faa860940440ef1ad3c
Merge "Drop 0.90 compatibility"