added OIndexReuseType.OPERATOR
Merge pull request #2232 from maggiolo00/custom-indexreuse

OIndexReuseType.OPERATOR
Merge pull request #2233 from kowalot/develop

Fixed execution of sql batch script when lines ending with \n
Null keys support was added in sbtree but without tests.
 massive insert removed all hooks, including OClassIndexManager,fixed
Merge pull request #2236 from maggiolo00/massive-insert

Massive Insert
Documentation
Merge remote-tracking branch 'origin/develop' into develop
Fixed issue #2228
Refactoring of OTransactionOptimistic. Fix warnings.
Explain: added new context variable involvedFields when indexes are used
Merge branch 'develop' of https://github.com/orientechnologies/orientdb into develop
JSON: Fixed issue introduced with last commit
Minor: improved thread names

Included ALWAYS OrientDB, on plocal threads added database name, on
http connection the local/remote host/post
Added default value for variable parsers
Added OClass.addCluster() + Fixed distributed schema management
Distributed: fix issues with schema
updated Studio
Improved creation of class from remote

class+cluster are created at the server side with just 1 call
Supported writeRecords also of arrays