Updates generate.php with command options

It should now only generate missing fixtures by default unless the
-r switch is used to refresh everything.
Fixes ArchiveReader::unpack()

For the last time, hopefully. Should be a bit quicker, too.
Adds RarInfo sanity checker for File header blocks
Adds support for analysis byte ranges

This also includes general improvements to basic file/data handling.
Adds RecursiveRarInfo class