Test Node send for req/res behaviour.
Test Node status method.
Adding unit tests for credentials.extract
Merge pull request #310 from hindessm/more-node-tests

More tests for the Node base class.
Merge pull request #311 from hbeeken/test-credentials-extract

Adding unit tests for credentials.extract
Add webSocketKeepAliveTime setting to aid testing.
Add comms keep alive tests.
Remove redundant assignment.

The publish immediately overwrites this time so there isn't much
point setting it.