0.2.0

• Recording start and update timestamps for every build step
• Cleanup old endpoints: /api/pipeline and /api/pipeline-state
• Improve retriggering: Create a new pipeline-run instead of overwriting existing builds
• Make bash-step killable
• Breaking Changes:
  • removed core/mk-pipeline as a method to initialize the pipeline.
    Replaced with a more flexible core/assemble-pipeline and a few single functions that take over things like running
    the pipeline and providing ring-handlers to access the pipeline. For details, see examples.