Dht routing code normalization

So I started checking the DHT code by looking at the kbuckets.py code, and I decided to write a couple simple unit tests which immediatly failed due to issues related to nomenclature and typos.

Therefore I started to normalize the classes attributes to not have a "_" prefix, and avoid any possible confusions in the future. In the end python doesn't have real encapsulation, and the "_" and "__" effects to how things are exposed can be easily overcomed, so this commit is to favor simplicity and avoid future headaches that will only be found during runtime.

These are just renaming refactors, nothing big, I'm sure there's still a lot more to be done.

Let me know if I should merge, so that we can continue to work on more solid ground all the p2p code.