Implemented ring discovery from a single seed node.

There are now two new methods in the module and unit tests
for them:

discover() - takes a seed node in host:port format and returns a list
of peer nodes in the ring

discoverPool() - takes a seed node & a connection options object &
returns a fully-configured (but not connected) ConnectionPool ready
for use

Began using must.js instead of chai for test assertions. I haven't
migrated any existing tests.
Documented the new ring discovery functions.
Bumped version in preparation for release.