support gzip request content
Merge pull request #1382 from henryzhao81/master

Support GZIP request content
Fixed ObjectDatabase delete orphan: wasn't executed in tx
Merge branch 'master' of https://github.com/nuvolabase/orientdb
Server: fixed import file/db commands, improved speed on creation of HTTP connection and supported stateful commands in server XML configuration
Fixed distributed cfg
Renamed OFlattenIterator in OMultiCollectionIterator allowing generic types
Fixed issue #1389 about concurrency problems on Pool.acquire()
Minor: added asserts in test case
Update path of OrientBatchGraph after BP refactoring
Get record metadata support for binary protocol was added.
SQL: "group by" now supports context variables
Merge branch 'master' of https://github.com/nuvolabase/orientdb
Minor: removed warning about Unsafe usage
MMAP was drop for hash index and new disk buffer was added.
Local hash table abstraction was added.
Iteration functions were added into hash table.
Local hash table test was added.
Local hash table tests were added.
Iteration  tests were added in local hash table.