Lots of changes for divorcing the node-router. New "observable" mechanism.
The node-router is now divorced from the core of SMCP.

But there is collateral damage. The timer-node doesn't work
at the moment. The variable-node work, but still inherits
from smcp_node_s (which will be fixed at some point).

The entire pairing system has been gutted, but it has
been replaced with the observable system. Pairing doesn't
work anymore, but observing still works, and the API
is much easier to use than the previous pairing API.

More updates coming.
Autoconf builds are working again.
More updates.
Lots of updates to documentation, architecture.
Lots of documentation updates.
Updates to documentation, added travis info, added a test suite.
Fix for travis build error.
More test suite updates.
More documentation updates.
Version bump to 0.6