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
do $specifications same as in Select object
add alignColumns() and fix getRawState()
#5142 - cleaning up docblocks
#5142 - turned `protected` members into privates, as the class has standalone functionality and is based on `AbstractSql`