Merge pull request #54 from dowski/zmq-service-durability

ZMQ Service Durability
Version bump
A start on a Buffer C extension

Compiles, prints a repr, allocates some internal storage, accepts data
via a `feed` method.

Very much a work in progress (e.g. It'll blow up if you feed it more
than 100 bytes).
Support for growing the buffer

As more data is fed in, the buffer will grow as needed.
Exposed a partially working set_term method

Supports str and int terms right now. Likely breaks spectacularly if
some other object is provided.
Correctly handle NUL bytes in feed and repr

Buffer_repr is pretty gross now though. Could definitely be cleaned up,
but it's just the repr so I'll save it for a rainy day.