Thetagang

* Bump version.

* Wait for order status to leave pending state.

* Config: replace `minimum_cushion` with `margin_usage`.

I found the concept of maintaining a minimum cushion to be too hard to
reason about, and it didn't properly reflect margin usage in a way that
made sense to me.

Thus, I've replaced it with `margin_usage`, which allows you to specify
how much margin to use as a factor of the net liquidation value. I find
this to be much better.


* Update thetagang.toml

* Bump version.

* Fixed readme typo.

This resolves 1.


* Add note about symbols/weights.

* Add more detail to readme.

* Always stop main loop, fix position roll count.

* Fix open interest check, improve logging.

* Optimize Dockerfile.

* Improve config validation.

Raise an error when the weights don't sum to 1 or there are no symbols
defined.


* Improve log messages.

* Bump version.

* Fix deploy workflow.

* Bump version.

* Reformat position output.

* Add note on having enough money to get the money.

* Fix pnl calculation, add test.

* Remove extraneous print().

* Use 1 docker workflow instead of 2.

* Fix push command.

* Bump version.

* Update README.md

* Update README.md

* Update README.md

* Use separate docker hub/github docker workflows.

* Add slightly more detail to README.md.

* Update sample config.

* Add COPYING.

* Add sample ibc-config.ini.

* Add note about using a paper account to README.

* Add shutdown message.

* Add basic config validation.

* Bump version.

* Bump version.

* Update readme.