Log Message:
Update ruby-zip package to 0.9.1.

Also install some documents and examples.

= Version 0.9.1

Added symlink support and support for unix file permissions. Reduced
memory usage during decompression.

New methods ZipFile::[follow_symlinks, restore_times, restore_permissions, \ 
restore_ownership].
New methods ZipEntry::unix_perms, ZipInputStream::eof?.
Added documentation and test for new ZipFile::extract.
Added some of the API suggestions from sf.net #1281314.
Applied patch for sf.net bug #1446926.
Applied patch for sf.net bug #1459902.
Rework ZipEntry and delegate classes.