User murmur instead of md5

[stefanmb]

MD5 is disallowed in FIPS mode, use a pure JS version of murmur instead.

Resolves #5

[stefanmb]

@othiym23 Any feedback on this? Thanks in advance!

[othiym23]

I'm working on landing this, but also making sure that the tests work properly in Node.js 0.8 at the same time. I also took the opportunity to bring this package under npm's umbrella of using standard for CLI-related packages, and so I made a few tweaks to your patch to match standard style, but the changes themselves look good. I'll get this landed later today.

[othiym23]

OK! I rebased and landed this as dfaac1b, which is included in [email protected], which will be included in the next versions of npm@2 and npm@3. Thanks for your patience, and thanks for putting this together!