Allow rules to contain many parts.

Rather than having a single "header" + "regexp" for each rule we've
now relaxed things such that rules can contain an arbitrary number
of header+regexp pairs.

For a rule to match each part must match, allowing definitions like:

    status:404 method: "(put|post|delete)"

This closes #1.
Added
add WordPress and Drupal authentication failures (though these are only suspicious)
add detection of some generic SQL injections in query strings
anybody looking at revision control system files is likely scouting for vulns
various WordPress exploits and signatures of scanning for them