v0.3.0

[sjfleming]

This is a major update to v0.3.0, with several big changes from v0.2.0 that will hopefully

• Improve accuracy
• Reduce cost of the workflow
• Improve the user experience

Closes #5 , #7 , #38 , #68 , #80 , #84 , #85 , #87 , #93 , #95 , #97 , #98 , #99 , #105 , #107 , #119 , #121 , #123 , #124 , #128 , #141 , #146 , #150 , #156 , #160 , #180 , #184 , #190 , #191 , #205 , #207 , #209

(a few more to be added...)

• Checkpointing, more input formats, HTML report, test suite, documentation, new posterior and estimators, fix readthedocs, improve prior heuristics, Github actions for tests, address memory issues