feat(controller): add endpoint and infrastructure for limiting memory/cpu
feat(client): add commands for managing memory/cpu limits
docs(client): add more clarity to limit:set
docs(client): more clarity on limit:set options
docs(reference): add deis limit autodocs
ref(client): rename limit to limits

'limits' follows our other commands' syntax much better i.e. apps:list,
releases:rollback etc.
docs(client): more clarity on limits:set
ref(client): move options from argument list
fix(client): move options list before arguments

Docopt does not allow additional commands after ellipsis as it's hard
to determine when they end (e.g. is this argument an arg or an option?).
ref(controller): move limits to Config model

A Release is a Build and a Config, not a Build, Config and a Limit.
Limits make sense as configuration for the Build, so this moves it
over as a Config field.
style(client): flake8
fix(controller): rename /limit to /limits
docs(controller): add Limit server autodocs
style(controller): revert code folding
Merge pull request #1513 from deis/resource-limits

Memory/CPU limits for application containers