fix(controller): revert to `start proctype` for buildpack images
fix(builder): send nil to controller, not 'False'
fix(builder): parse release info correctly

Release info was being parsed improperly. We should only fall back to
the Procfile if we cannot find any default process types from the
release info.
Merge pull request #2673 from bacongobbler/no-bash-wrapping

fix(controller): revert to `start proctype` for buildpack images