The new probe will convert all node's LatestControls to Controls, so
the old app can consume them. Also, the new app will convert all
node's Controls to LatestControl, so it can consume the reports from
old probes.
Squash of:
- use detailed.Summaries to render topology nodes
- ban merging nodes of different topologies (they should be mapped)
- need to prune parents when mapping node types
- render container images by id if they have no name
- remove separate render ids and prune parents in NewDerived*
- don't render metrics/metadata for groups of nodes
- fixing up tests
- removing pending unit tests (for mapping.go, for now)
- updating experimental dir for RenderableNode removal
- All HostMetadata information becomes NodeMetadata
- Significant change to mechanics, but same net effect
- LocalNets becomes "local_networks", space-separated list of CIDRs
- Load becomes simple single string
- Use MakeHostNodeID for indexing into Host topology
- (That changes the app /origin/{id} handler; will be removed later)
