#10 Function to delete stale hosts

[Frosty192]

There is a function to delete url's from the database
after MAX_AGE but there is no function to delete host
ip's. For example gzip.bounceme.net/gwcii.php?stats=1
has 20,000+ hosts stored.

The result of this is that a huge number of stale hosts
are stored and when the script selects this bloated
table it may put a heavy load on the server.