#271 add proxy with auth,

this is workaround for #271. but this code has not been tested, since i do not have test environment and our client who had this trouble somehow resolved this problem before I create this patch. I just create PR not to forget code.

if you find someone with proxy/auth trouble , please check if
https://gist.githubusercontent.com/k-okada/cf79038d1cffc943a8d3/raw/b4d21725af7de2ac318d5a27ca6003bb1e6e0d95/rosdep work

this workaround is based on http://stackoverflow.com/questions/34079/how-to-specify-an-authenticated-proxy-for-a-python-http-connection

What is the scope of this call. It looks like it will set the opener for the duration of the program. I should probably use the non persistent call or cache the OpenerDirector object from the documentation you can just call "otherwise, simply call OpenerDirector.open() instead of urlopen()." which won't override all calls.