Removed svn keywords, more POSIX compliant shell scripts
Removed the subversion keywords $Date$, $Id$ and $Rev$ from all files.
Added centralized versions information from VirtualMailManager.constants.VERSION
to many files.
install.sh and upgrade.sh do now strict POSIX compliant string comparison in
expressions. Fixed a type in upgrade.sh.
Updated copyright information
- Aliases
    - avoid looping aliases
- Domain
    - optional limits for number of:
        + accounts
        + aliases
        + destinations/alias
        + alias domains