Rename Collector::generateInstallationId() to getInstallationId().
Make Collector::getInstallationId() public.
Also use encryption key to generate installation id for more uniqueness.
Remove lokal IP range exclusion.

After discussion with xtra, exclude local IPs is a bad idea. On the one
side we collect data from development and testing installations, on the
other side we may exclude installation that are behind a caching or SSL
proxy or just behind a firewall in a LAN.
Improve inline documentation.