Prepare for refactoring of hosts-legacy.txt to some other baseline file
Prepare for refactoring of hosts-legacy.txt to some other baseline file

Cull dead hosts; dead for this purpose means all hosts that don't resolve
to an A record and don't have an MX record.

Flatten more groups of hostnames into full-domain blocks, e.g. popupad.net

parseword/nolovia,ampersign/nolovia