Fix history_metadata accesses for unusual symbols

[sdeibel]

Fix format_history_metadata when firstTradeDate is None, as is the case for QCSTIX and probably others. Submitting this on main since it seemed appropriate for that based on the instructions in #1084 -- I can redo it if that is not what you want.

Fixes #1410

[ValueRaider]

main is fine for this. I've updated unit tests (they should have detected bug), which found some other related issues. I don't have time to use, let me know if anything broken.

[sdeibel]

I don't think there are new problems but found that requirements.txt was missing requests-cache and scipy so I updated this pull request. Actually, I meant to make a new separate pull request but that didn't got as planned...

[ValueRaider]

Those two modules aren't necessary so deliberately missing.

• requests_cache - if user smart enough to want to cache, they're smart enough to install
• scipy - my sense is usage of price repair is rare (where scipy used)

[sdeibel]

There were needed to run the unit tests, which is what motivated me to add them. I suppose another idea would be to add a requirements-test.txt but it's not a big deal since it's pretty obvious what's needed when trying to run the tests and only two things had to be installed.

[ValueRaider]

I deleted that commit

[sdeibel]

Great, thanks.