refactor(makefile): remove fleet, switch to deisctl and custom images
fix(user-data): restore default discovery url
docs(readme): update root readme with new deisctl instructions
docs(hacking): new docs for hacking on deis
fix(readme): address feedback, fix typos
fix(makefile): default to 3 nodes, test for docker binary
docs(readme): add hack instructions to readme, remove newline
ref(Makefiles): use $BUILD_TAG, which defaults to "git rev-parse"
ref(tests): use images from "make build" in component tests
fix(user-data): add fixed version of sed command to "make discovery-url"
fix(tests): improve functional test setup logic
feat(tests): add end-to-end acceptance test script for vagrant
docs(*): update documentation for new deisctl provisioning workflow
fix(Vagrantfile): specify AMD network to work around transfer issues
fix(contrib/gce): fix docker storage being wiped on boot

Ref: #1868
Merge pull request #1799 from gabrtv/new-devenv

Introduce deisctl and new cluster-aware development environment
fix(controller): fix scale log event on git push
Merge pull request #1883 from Xe/fix/gce/no-more-nuking-data

fix(contrib/gce): fix docker storage being wiped on boot
tests(docs): add documentation tests to test-acceptance script

Also fixes a missing import in docs/docs_requirements.txt.
docs(readme): cleanup readme after deisctl integration

docs(*): replace DockerHub with Docker Hub

doc(readme): change to approximately

docs(readme): replace sed with make discovery-url