Merge pull request #14 from avsm/master

NETWORK changes
Merge pull request #15 from avsm/master

Expose a DEVICE.id function to retrieve the id from a built device.
Merge pull request #16 from avsm/master

Modify `NETWORK.read` to be `NETWORK.listen` to match implementations.
Improve Travis scripts to pin/install an upstream dep
Simplify build system to not use `ocamlbuild`.