security: disable per webhotel webmail

a few issues with the installation of squirrelmail on linux

1) everything is world writeable
2) every webhotel has its own copy

maybe both are needed for squirrelmail - have not checked this webmail to much, but both issues are not good for us. "world writebale" is in anycase strange setting, but having one copy of webmail per webhotel is in our book not good design.
Since we also do not want to/do run mail on the www server we would prefere that the admin had an option to disable installing webmail in the first place. Alt least install only one server wide copy and alias it to make it secure/updatable or in our case, dont install it at all since we want to be able to install webmail directly on the dedicated mail server to again enhance security and mangagebility.

World Writable group permissions will fix in build5.

Regarding, using squirrel mail global directory we will forward this request toward concern department to review the implementation.

ok, super. Or simply a feature to disable installing webmail altogether to allow the host to deside for an other setup like installing it directly on the mailservers and simply ask users to access http://mail.mydomain.com