Add Verbose Extraction Flag

[gfs]

Currently if you set ExtractSelfOnFail you'll the parent archive but not any (limited) contents that we were able to extract out of the archive. Consider adding an additional flag for use with ExtractSelfOnFail that would also include everything we could find. This would require adding a field to FileEntry to indicate partially extracted file, perhaps with gradations of how much was extracted.

[gfs]

This could also use the FileEntryType enum (is this the right name for the enum type?) to indicate a shell result (ie dont expect a valid Stream in the FileEntry).