Implemented .finally(fn), fixing #25

[Kaelinator]

I am not completely sure if this is implemented correctly. Personally, I have never used .finally, but I read up on its functionality, and have replicated the behavior.
Also, I'm debating whether or not I should merge impl-finally with my master branch...

[Kaelinator]

This is awkward, the commits on #13 are showing up here...

[justsml]

Thanks @Kaelinator

I've been thinking about Promise.finally() being added to the Promise spec.
I'm not sure I like how it's supposed to work. Kinda makes my techniques harder to reason about. I need more experience with it before I firm up my opinion however. I need some time to think about this some more...

Here's my current thoughts: I'm trying to emphasize that functional-promises is NOT itself a promises replacement.

Adding every feature from Promises into the FP API muddles the message. I should have clarified this on #25

Thank you for the PR, the code looks good - and follows the project style. 👍

Let me know if I missed anything. 😺

[justsml]

As for the mix of commit history, this happens 100% of the time on 2nd commits. (and sometimes I forget this key step) ;)

You need to pull from the upstream master, merge it into your local master - then create the new branch.

The key is to checkout the upstream master branch, then create the new branch to work on.

If you do it out of order, it's often easier to start a fresh branch and manually copy desired changes back in.

[justsml]

Ping me on slack if you need some help with the commands...

Let me know if you want to do a pair programming session in the evening this or next week - I need a 2nd set of eyes - been working on a strange bug. 🤔

[justsml]

Closing for the moment, putting feature on backlog...