Added support for GET on unencrypted port to inform user about convergence and used verifier

[scm2342]

I added support for a HTTP GET on the unencrypted port. Convergence will look at a html file named .html in the verifier directory. If this file is found, then its contents is served, otherwise the class name of the verifier is returned. This behaviour can be overwritten in the verifier subclasses. I also added a concise description for the Network Perspective Verifier. The sample output can also be seen at http://punk.hamburg.ccc.de:8080 (with changed logo - the version in the commit contains the Convergence logo)

[moxie0]

Seems like we should use the TLS port and have the code spit out the markup rather than serving a file?

[mk-fg]

5ec373ccfd8c41198d324509232a6ec9e67d67dc should apply relatively cleanly on top of 7f35837 and:

• Do putChild for notary Resource on TLS port, instead of overloading existing methods.
• Allow Verifier to have arbitrary html_description attribute or getDescription method to return html string or IRenderable (twisted.web.template) to be rendered within a standard template canvas by @bigmac2k.
• For Verifiers with no html_template and overrides for these methods - render generic "Notary Type: ..." message there.
• Allow Verifier to have getInfoNode method to handle request as it sees fit (e.g. return error or defer it).