Sketch of implementation.
Merge remote-tracking branch 'origin/master' into configure-ports-247

Conflicts:
	flocker/node/_deploy.py
	flocker/node/_model.py
Fixed broken import
Default proxies on StateChanges
Passing tests for deployer init setting _network
Improved test name
Explicit that no_state_changes includes proxies
Start of test for ports_to_create
Completed (?) test for proxies_to_create
Start of test for proxy needs deleting
Start of having all proxies enumerated
Set of proxies now doesn't break
Improved TODO
Started Flake8ing
Added TODO
Further Flake8
Further Flake8
Flake8'd test_deploy
Fix some long lines
Add test docstrings