Issue 71 creedsolo

[christakahashi]

implemented global variable swapping for creedsolo.
added a test for multi-instance creedsolo.RSCodec.

[lrq3000]

Thank you so so much, and I am very sorry for the delay in my replies and processing, I had an unexpected huge continuous workload that I have no choice but to complete for the sake of my family.

I should be soon be able to process your PRs. The main slowing issue is that the Github Actions automated unit testing broke, so I need to update that first before merging anything.

Thank you so much once again for your contributions, your patience and your understanding.

[christakahashi]

No worries! I hope everything works out! I'm in a similar situation but it just so happens that this project is related. For the time being I've just integrated the my fork into my project and it'll switch back to the official reedsolo package automatically when it sees a newer version.