Add wire protocol compatibility info to TopologyDescription.
Merge pull request #11 from ajdavis/add-wire-protocol-compatibility

Add wire protocol compatibility info to TopologyDescription.
Finish down-casing hostnames in tests.

Some tests added on another branch while hostnames were canonicalized
to lowercase on master.
Use "topologyType" in remaining tests.

Some tests added on another branch while "cluster" was being replaced
with "topology" on master.
Merge pull request #12 from ajdavis/lowercase-hostnames-in-tests

Fix server discovery tests.