Break package out to not depend on vapor

[kylebrowning]

Some hyper performant applications that are running swift, may not be using vapor. It would be nice if this package didn't depend on a vapor, and there was a new package specifically for vapor so that apps/programs could important the dogstatsd and not have to pull in vapor

[gh123man]

Thanks for the feedback. I was thinking the same. Probably a:

• Dogstatsd NIO package.
• Dogstatsd Vapor package that depends on the dogstatsd-NIO

This way users can choose if they want the vapor specific interface, or the lower level library directly on top of NIO. Does this sound good to you?

[kylebrowning]

Yup, that's exactly what I was thinking.