Allow construction of wrapping iterators with iterators

[JeroenDeDauw]

Right now the only factory functions exposed take a reader:

public function newObjectDumpIterator( DumpReader $dumpReader, callable $onError = null ) {

public function newEntityDumpIterator( DumpReader $dumpReader, Deserializer $entityDeserializer, callable $onError = null ) {

This means one cannot decorate behaviour of the wrapped iterators, such as applying a LimitIterator on the lowest level (and not still end up doing deserilaization).

Can be solved by adding:

public function newObjectDumpIteratorFromIterator( Iterator $stringDumpIterator, callable $onError = null ) {

public function newEntityDumpIteratorFromIterator( Iterator $objectDumpIterator, Deserializer $entityDeserializer, callable $onError = null ) {