Freebsd 10 platform

Not sure if you're interested in supporting FreeBSD, but I just tested these changes last night on my FreeBSD 10 box using Python 2.7.x and pip from pkgng. Everything seemed to work fine.

Curiously, the FreeBSD port of mitmproxy (see: http://svnweb.freebsd.org/ports/head/www/mitmproxy/) doesn't seem to have any patches like this and so I'm unsure how it's working for them and haven't tested the port. I can test and submit a patch there instead if it is preferred, but this 'upstream' fix would eventually make the port usable if it's broken.

Thanks for the great software!