Please use logging!

This adds a package wide logging-configuration mechanism and adds
some explanation to README.
Merge pull request #35 from brainbot-com/logging

Please use logging!
Merge pull request #36 from brainbot-com/p2p_wire_rb

Actively discover and manage peers
rlp.decode also returns strings
validate receiced peer addresses
read long packets
fix peer pings
fix send peers
don't connect yourself
exit if port is already used
added support for command line options