First working tunnel.

Huge security problem,
***THIS INITIAL RELEASE OFFERS NO SECURITY***
the keypool is reused over and over again from byte 0. This is just an initial commit.
Update README.md
Readded the lines to drop packets not intended for us.
Heavy refactor, first test.
removed pytun import
Fixed encode and decode functions to always use bytearray for input.
No longer cares what you set as the tap_addr
Added debug statments. Changed default netmask to 24.
Fixed diagnostic messages / tab indentation