update msgio (combine)
util/log: SetDebugLogging
crypto/key: stretcher refactor
msgio proper write
secio -- spipe v2

This commit introduces secio, the next generation spipe.
seccat (to test sio)
secio: better handshake log msg
secio: encrypt copy

sadly, encrypting needs to copy, as the user supplied buffer
must not be mangled.
Update interface.go
Update interface.go
added log.Events to secio
secio unexpose bufPool
Merge pull request #442 from jbenet/io-spipe

secio, spipe replacement