Some cleanup plus packaging enhancements.

- AIX: Changed the pre-deinstall script to unconfigure
       to address an issue where failed deinstallations
       caused follow-on problems
       Changed pre-install script to post-install and
       added additional link
       Removed typo in AIX Makefile
- Solaris: Removed symlink from /usr/bin to allow installations
           into local zones
- README.install: moved up one directory