Change format of how values are returned.

Use a standard signature of (nodeid, commandclass, value), where value
is an object containing commandclass-specific entries.  This allows us
to be flexible with different classes.
Enable verification of value changes.

Previously we were getting 'value changed' events even when a value
didn't actually change.  By using SetChangeVerified() we now get
ValueRefreshed notifications instead, which we simply ignore.
Support COMMAND_CLASS_VERSION.
Improve clarity of default switch statement.

Fixes part of jperkin/node-openzwave#8
Fix homeid output.

Fixes part of jperkin/node-openzwave#8.
Update example application for recent changes.

Also add a condition on 'node ready' for printing out value changes, so
that we do not get spurious updates when the node is first scanned.
Update docs with recent changes.
Version 0.0.17 for recent changes.