[TEST] remove trace logging
Aggregations: Fixed failures when geo points are all either positive or negative
Indexing: clear versionMap on refresh (not flush) to reduce heap usage

The versionMap holds all versions (keyed by _uid) for recently indexed
documents.  Previously we only cleared it during flush, which can be
infrequent if the translog flush thresholds are high, and can cause
excessive heap usage especially for small documents.

Now we clear it during refresh which is usually more frequent
(e.g. once per second by default).

Closes #6379
Add Javadoc
[DOCS] Add special attributes for indices allocation filtering
get -Dtests.verbose passing through Maven
add versioning test
Core: switch to the new ConcurrentHashMap implementation coming in Java 8

The new implementation has lower RAM overhead and better concurrency
in some cases.

Closes #6400
Scripts: exposed _uid, _id and _type fields as stored fields (_fields notation)

The _uid field wasn't available in a script despite it's always stored. Made it available and made available also _id and _type fields that are deducted from it.