Adding configuration to support corporate http proxies for webdrivers fixing issue https://github.com/theintern/intern/issues/197

...er configuring optional httpProxy. Updated wd dependency to current version, as proxying is a new feature not supported in earlier versions.

As of issue https://github.com/admc/wd/issues/307 the usage of coporate http proxies is mandatory for many developers. 

Whilst sauce connect may be started seperately on a corporate server using a proxy configuration the embedded webdriver, setting the sauceJob status via get (according to issue https://github.com/theintern/intern/issues/197) does not provide proxy config as for now. 

Since the wd module supports proxy settings since the most current version, the porssibility to configure it via intern is now possible as well. 

I tested the code for my setup and it worked well. As I'm not that familiar with intern.js in other terms please check for compatibility with the 0.3.0 version of wd needed to support the http proxy. 

Unfortunately I didn't succed in adding proxy support to sauce-connect-launcher as well as other issues occured. I remember reading somewhere that as of intern version 2.0 sauce-connect-launcher will be removed anyway? 

If the pull request is accepted I'll provide a more detailed overall tutorial for using intern.js with a coporate proxy (How to setup sauce-connect, what to change in the intern.js config, how to automize ip detection etc...)

Regards, 

Flowkap