Multipass Support

[mzuenni]

TODO:

• [x] parse problem.yaml
• [x] change generate
• [x] change validate
• [x] change run
• [x] change run interactive
• [x] change test
• [x] change test interactive
• [x] handle latex multipass samples
• [x] handle latex interactive multipass samples
• [x] improve verdict ui (show pass)
• [ ] ???

[mzuenni]

@RagnarGrootKoerkamp @mpsijm is there more to do here? (besides that this is not properly tested...)