Add Bugzilla integration
bugzilla/index: remove unwanted require
bugzilla/config.json: remove optional options

Write sane defaults to the platform and the op_sys fields as Bugzilla
demands their presence despite of their optional nature described in
the docs.
bugzilla/xmlbuilder.coffee: escape XML for strings
bugzilla/{bugzillarpc,index,xmlrpc}: don't throw errors

Use the proper way instead. Thanks @ConradIrwin for guidance :)
bugzilla/{bugzilla,xmlrpc}.coffee: refactor XmlRpc object

It turns out Node.js caches[1] module.export objects.

http://nodejs.org/api/modules.html#modules_caching
bugzilla: add icon.png

The official announcement:
icon.png was optimized by ImageOptim, which saved us 3.7% of space!
bugzilla/xmlrpc: fix undefined callback
bugzilla/bugzillarpc: prettify template

I extracted the template to an external file because heredocs break
indentation for the Stacktrace traces.
bugzilla: exclude Project from the list of fields

It should be fine to just have URL.
Merge pull request #79 from kyrylo/bugzilla-support

Add Bugzilla integration