Merge branch 'cs/#6699-zend-dom-psr-2-compat'

Close #6699
added zendframework/zendxml into require at Zend\Json's composer.json
move zendxml to suggest and mark to Json::fromXml() as @deprecated
update comment on suggest
PR #5001 - transaction API unification
#5001 - avoiding overriding docs for inherited/implemented methods in `Zend\Db\Adapter\Driver\IbmDb2\Connection`
#5001 - avoiding overriding docs for inherited/implemented methods in `Zend\Db\Adapter\Driver\Mysqli\Connection`
#5001 - avoiding overriding docs for inherited/implemented methods in `Zend\Db\Adapter\Driver\Oci8\Connection`
#5001 - avoiding overriding docs for inherited/implemented methods in `Zend\Db\Adapter\Driver\Pdo\Connection`
#5001 - avoiding overriding docs for inherited/implemented methods in `Zend\Db\Adapter\Driver\Pgsql\Connection`
#5001 - avoiding overriding docs for inherited/implemented methods in `Zend\Db\Adapter\Driver\Sqlsrv\Connection`
#5001 - Fixed default values and docblocks in `Zend\Db\Adapter\Driver\AbstractConnection`
#5001 - Implemented missing docblock in `Zend\Db\Adapter\Profiler\ProfilerAwareInterface`
#5001 - cs fixes and cleanups in the transaction PDO connection tests
#5001 - license headers and PSR-2 compliance for `PdoMock`
#5001 - license headers and PSR-2 compliance for `PdoMock`
Merge branch 'feature/#5001-transaction-api-unification' into develop

Close #5001
implement multiple combine statement
add docblocks
do getRawState() same as in other objects