[PATCH] Fixed unchecked typecasts of DcmItem::search results.

[PATCH] Fixed unchecked typecasts of DcmItem::search results.

DcmItem::search() returns a stack of DcmObject pointers as search results.
These pointers in most instances need to be casted to DcmItem, DcmElement
or a subclass of these. In many cases, the type of the object was not
properly checked before the typecast. This could lead to segmentation faults
when invalid DICOM datasets were processed where elements had the wrong
value representation.

Gbp-Pq: Name 0001-Fixed-unchecked-typecasts-of-DcmItem-search-results.patch