recommendation from Daniel Roethlisberger. TRACE is interesting because
it can be used to get cookies or authentication data in a cross-site
scripting attack. See http://www.owasp.org/index.php/Cross_Site_Tracing.
methods it discovers are in (GET, HEAD, POST, OPTIONS, TRACE). In
verbose mode, or if any other method is discovered, it prints all
methods (and optionally retests them). See
http://seclists.org/nmap-dev/2010/q1/401.
This script sends an HTTP OPTIONS request to get the methods
supported by the server, and optionally tests each method to see if
they are restricted by IP address or something similar.