Enable training auto-start

[maxpumperla]

@slinlee just tracking this here for sake of completeness. the start flag should do what it promises.

[slinlee]

yeah right now I feel like it stalls out asking for goals.

If we add that flag, it should just add all the reward terms together, right?

[maxpumperla]

yes, which would be in line with our discussion in #15. In any case, this shouldn't take priority.