Peter M. Groen / oletools

Looking for reason for ResourceWarning abount unclosed BufferedReader, but
this was not the cause...

All development and testing has been done with a singe, very simple,
self-made sample. On the road, found lots of other potential ways to
include data from external sources.

Often you want to know size of a stream or re-set it to start, both of
which are not provided by ZipExtFile (result of ZipFile.open). Implement
both in own class.

…acro security (issue #221)