Make adding "www" and "http" in traceroute() optional

[Andarin]

Hi,
I like your lib (found it over StackOverFlow) as it was the fastest I got running for my small use case.
I want to suggest one little change: make adding "www" and "http" in traceroute() optional. There are some sites, especially in intranets, which do not have a "www" redirect, e.g. "http://www.intranet" does not resolve to "http://intranet", thus handing an error when it shouldn't.
It was easy enough to patch your function, but I think it would be nice to have this functionality right away. I try to create a pull request later today or this week.
Cheers