Fixing in `connection`, `v3`, and `forward`.
Forwarder.setSink() no longer fires wrong deferred.
Fixed references in `manager`; `_writeAsBytes()`.
Debugging cell->str issues.
decode ASN.1 RSA public key from PEM to DER format in ntorhandshake
make create_onion_skin return str
Fixes in onioncell.py
Merge branch 'demo/connection_refactoring' of https://github.com/nskinkel/309Project into demo/connection_refactoring
Added craziness to Forwarder.
Added code to print out bytes that can't be made into cells.
Added DestroyCell support; setup demo with it.