Allow warmup iterations when not adapting

[WardBrian]

And, prevent adapting with no warmup

Submission Checklist

• [x] Run unit tests
• [x] Declare copyright holder and open-source license: see below

Summary

Closes #730

Copyright and Licensing

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• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (46f8608) 79.82% compared to head (af8a747) 79.85%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #731 +/- ## =========================================== + Coverage 79.82% 79.85% +0.03% =========================================== Files 75 75 Lines 11502 11502 =========================================== + Hits 9181 9185 +4 + Misses 2321 2317 -4 ```

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