feat(controller): expose app url

While users should not have access to view a cluster's private
information like the cluster's auth key or the list of machines,
we need the cluster domain in order to expose the app url to the
user.
chore(builder): bump cedarish image
chore(contrib/gce): make GCE script pass flake8

Also do a few stylistic changes:

 - prefer double quotes instead of single quotes
 - functionize commonly done tasks
 - use exit code
docs(installing_deis): clarify no web UI
docs(contributing/localdev): update localdev docs

[skip ci]
docs(reference): add `deis pull` reference
fix(builder): set /app as working directory for apps

When you run commands with Heroku, you are running under
/app as the intial directory.
test(controller): add unit tests for app-related permission checks
fix(controller): honor app permissions correctly on app-related views
chore(logger): update go to 1.3.1

Also updated to go 1.3.1 in our etcd test container.
fix(docs): remove coveralls badge and mentions of coverage stats

The "95% passing" badge is stale since we don't use Travis-ci.org now,
and regardless was only summarizing coverage on the controller/
subproject. It would be great to roll up the coverage stats we do have
in the Go and Python subprojects and summarize that number in the
README, but for now we should hide this misleading number. Likewise,
the .travis.yml file was removed as it can only lead people astray
at this point.
Merge pull request #1599 from bacongobbler/builder-workdir

fix(builder): set /app as working directory for apps
Merge pull request #1582 from bacongobbler/903-apps-open

fix(controller): expose app URL
Merge pull request #1603 from mboersma/logger-golang-131

chore(logger): update go to 1.3.1
Merge pull request #1602 from mboersma/1576-fix-deis-ps-perms

fix(controller): honor permissions on app-related views
Merge pull request #1592 from bacongobbler/localdev-docs

docs(contributing/localdev): update localdev docs
Merge pull request #1597 from bacongobbler/1484-pull-docs

docs(reference): add `deis pull` reference
Merge pull request #1591 from bacongobbler/bump-cedarish

chore(builder): bump cedarish image
Merge pull request #1605 from mboersma/hide-coverage-badge

fix(docs): remove coveralls badge and mentions of coverage stats
Revert "fix(controller): use /bin/sh as entrypoint for run"

This reverts commit 92cb26a054afff117e4c56f434cc00093d23a690.