Reduce public API as much as possible

[lukebakken]

Follow-up work from #713

As suggested by @bording in this comment

[bording]

#739 Was my first PR to reduce the public API surface, but I believe there are still more things that make sense to internalize. I'll be looking at those in a subsequent PR.

[lukebakken]

@bording thanks a lot for #739. I'm hoping to get an RC 1 of version 6 published by the end of March. Should I wait for a follow-up API pull request?

[bording]

I did want to make one more pass and see if there was any more cleanup that was worth doing, but I just haven't had the spare time to do it yet. Do you know more specifically when you'll be trying to get RC1 out?

I'll try and get it done before then.

[lukebakken]

I'm not going to rush anyone gracious enough to volunteer their time. How about by the end of March? There are still a couple issues related to bugs in the 6.0.0 milestone I need to investigate.

[bording]

How about by the end of March?

That should work!

[lukebakken]

Thank you we really appreciate it.