Here is a quick list of the modified files:
Archive - getDirectoryContents() no longer pure virtual
Archive.cpp - default getDirectoryContents() implementation
unzip.cpp - modified to fix a bug where the same file will not load twice in a row
ZipArchive.h / ZipArchive.cpp - extends osgDB::Archive and provides support for random access loading within a .zip file
ReaderWriterZip.cpp - modified to use the ZipArchive class"