Hazelcast Inc.
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'

Conflicts:
	hazelcast-documentation/src/main/docbook/manual/content/index.xml
https://github.com/hazelcast/hazelcast/issues/3567
IllegalMonitorStateException: Current thread is not owner of the lock! in Hibernate support under heavy load
Replaced `map.tryLock` based implementation in `IMapRegionCache.put` with spin loop around atomic operations.
Improved serialization framework to support more storage environments other than jvm heap (offheap, disk etc).
continue serialization changes
added memory package
Refactored NodeInitializer to NodeExtension
updated spi and partitioning system to support high density caching
Completed refactorings/code changes due to serialization changes.
findbugs and checkstyle
Introduced ClientExtension.
Client fixes and improvements due to serialization changes
test fix
serialization service refactor
Improved portable header read.
Code improvements
Fixed packet size.
Merged with latest master
cleanup