Add example/PoC of channels as files

[henesy]

This was discussed on the #inferno channel awhile ago.

Theoretically you could express a channel chan type as a file and read/write memory addresses through the channel file between programs (using fp register indirection?).

Theoretically this could mean that two programs could share data structures between each other assuming they are in the same Inferno instance and share the same loaded module definitions for the data, thus avoiding serialization of their data structures.

This is not especially useful as it would not function between Inferno instances (such as across networks).