Add draining_time to LBConfig for now
Add last updated time to LBNode
Add a step that sets a metadata item on a server
Change server status to NamedConstants rather than strings, and add DELETING as a state
Revert "Add draining_time to LBConfig for now"

This reverts commit 60abdbe269bf9b98d52dc117b032526f0cf1a467.
Revert "Add last updated time to LBNode"

This reverts commit 8fb1cbf313cbbbe510b84fb4ddb176b8eeab001f.
Merge branch 'master' into converge-draining
Add remove from lb helper function that handles draining and draining timeouts
Remove 'draining timeout' attribute per load balancer config
Oops, now should just be a float
Add function to drain or delete a server
Add replace delete server logic with _drain_and_delete_server, and change those tests to test the converge function operating on a scaledown instead
Small refactoring
Change ACTIVE, BUILD, and ERROR to NamedConstants, and do some test cleanup because load balancers with cheese is a list
Move draining timeout from a per-node load balancer config attribute to an attribute in desired state
Add a SetMetadataItem step
Rename a variable to something maybe more clear
Remove draining timeout comparison test
Merge pull request #729 from rackerlabs/set-metadata-step-and-convergence-cleanup

Set metadata step and convergence cleanup
Merge branch 'master' into converge-draining