Settings / Config: Allow to explicitly specify external environment variable syntax, in which case its optional
fixes #2855
release searcher in finally block rather than relying on an exception that is thrown
confusing code..., but we can't release the searcher in a get result case
we need that searcher later on..., need to think of how to simplify that..., added a comment for now
Get template should return warmers

Fixes #2868
upgrade to netty 3.6.5
only return primary if it is active in PlainOperationRounting

Closes #2896
Properly cache parent/child queries and filters in the case they are wrapped in a compound filter.
Closes #2970