Twisted Web 15.4.0

Twisted Web depends on Twisted Core.  pyOpenSSL
(<https://github.com/pyca/pyopenssl>) is also required for HTTPS.  SOAPpy
(<http://pywebsvcs.sourceforge.net/>) is required for SOAP support.  For Quixote
resource templates, Quixote (<http://www.quixote.ca/>) is required.
