fix(controller): remove /run/deis/determine_registry

This script is backwards-incompatible with existing clusters. Moving the
calls to etcd directly into the unit file removes the dependency and
ultimately makes master backwards-compatible again.
Merge pull request #1512 from deis/remove-determine-registry

fix(controller): remove /run/deis/determine_registry
feat(controller): add endpoint and infrastructure for limiting memory/cpu
feat(client): add commands for managing memory/cpu limits
fix(controller): tack on host/port to image id

With the changes to how we store images in the controller, we stripped
the host/port from the image. We must add it back if we want to pull
it from the registry.
Merge pull request #1517 from deis/hotfix-apps-run

fix(controller): tack on host/port to image id
tests(integration): add check for systemd unit file droppings
tests(integration): document regression test for `clusters:update --auth=`

We already had a regression test to ensure the deis CLI wasn't just
sending the key path when updating the cluster. This change makes that
clearer and clarifies the output of the `CheckList()` test function.
fix(builder): bump timeout to 30m

The builer component times out not infrequently because it pulls
deis/slugrunner and deis/slugbuilder. Sometimes, if the Docker Hub
is slow, it takes several tries to get this running. Bumping the
timeout isn't a solution, but it is hopefully a stopgap.
Merge pull request #1523 from deis/test-regression-unitfile-removal

tests(integration): add check for systemd unit file droppings
Merge pull request #1524 from deis/bump_builder_timeout

fix(builder): bump timeout to 30m
Merge pull request #1525 from deis/test-regression-auth-update

tests(integration): document regression test for `clusters:update --auth=`
chore(client): remove unused client tests

We use integration tests to check the expected output of certain
commands. These tests have been unused and unmodified in quite some
time. Maybe when we rewrite the client in Go, we can draw upon these
for inspiration, but right now they aren't doing much.
docs(client): add more clarity to limit:set
docs(client): more clarity on limit:set options
docs(reference): add deis limit autodocs
Merge pull request #1526 from deis/remove-client-tests

chore(client): remove unused client tests
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