fix(builder): do not check for a Procfile

Some applications do not have a Procfile present before a buildpack
compile step[1]. If a Dockerfile is not present, then the builder
should make the assumption that this app is a buildpack app.

[1]: https://github.com/bacongobbler/heroku-buildpack-jekyll/blob/master/bin/release
fix(registry): store apps as appname

Storing the image in the registry as user/appname introduces a couple
of confusing ideas:

- images are implied to be unique across accounts
- images are owned by one user and one only

Point 1 is incorrect. App names are completely unique across the
entire cluster[1]. Point 2 is incorrect as well because apps can
be shared with the `deis perms` command. Changing the name of the
image in the registry from `user/appname` to `appname` makes the
image names unique across the entire cluster as well as making the
images more easily sharable between users.

fixes #729

[1]: https://github.com/deis/deis/blob/d1e14a6f76789a86f1959ba7bf6057b3abe3b960/controller/api/models.py#L109

BREAKING CHANGES: because this changes the way that applications
are stored in the registry, this is a backwards-incompatible change
with applications prior to this commit. To migrate over to this change,
you'll have to destroy and re-create your apps with the same name
as it was before. The docker layers from previous builds will still
exist in the registry, but the repository names will be changed
to reflect this change.
fix(controller): remove username length validation

This fix that was implemented in #631 was a bit hackish, and was
only used because we stored the images as username/appname in the
registry. The registry has a restriction where the username has
to be greater than or equal to 4 in length. Now that we are not
storing the images with the associated owner's username, we no
longer need this restriction.

reverts #631
fix(controller): give processes unique counters

Previously, when a container was created through App.scale(),
it would give the container a number based off the highest
container number amongst all containers available for the application.
This has been changed to give the container a number based off the
highest container number amongst all containers with the same process
type.

fixes #769
Merge pull request #890 from deis/769-unique-process-counter

fix(controller): give processes unique counters
fix(client): return 1 on two more error cases

`deis:register` always seemed to succeed in integration testing,
even when it didn't.
Merge pull request #940 from deis/more-cli-return-codes

fix(client): return 1 on two more error cases
chore(builder): update docker to 0.11.1

http://blog.docker.io/2014/05/docker-0-11-release-candidate-for-1-0/
Merge pull request #901 from deis/remove-username-registry

fix(registry): store apps as appname
Merge pull request #876 from deis/no-procfile-check

fix(builder): do not check for a Procfile
Merge pull request #944 from deis/builder-docker-0.11.1

chore(builder): update docker to 0.11.1
feat(controller): add Domain model

This is added in the API with 2 new URLS

GET /apps/{app}/domains to retrieve the list of the domains
POST /apps/{app}/domains/{domain} to create a new domain.

The CLI is adapted to make use of this new API.