build(readme): update `README.md` in place

It is too easy to forget to update the readme
after editing the template.

feat(cli): add option `-I`/`--replay-stdin`

v2.4.0

feat(cli): refer to Fibonacci backoff next to exp

Update matching places in the readme.

feat(cli): add option `-r`/`--reset`

test: fix `TestConditionTotalTime`

build(version): bump to 2.0.4

build: stop using subdir approach for v2

build: move v2 to `v2/`; restore v1

I made a mistake and didn't apply the proper directory structure
in the v2.0.0 release.
In retrospect, I should have kept recur a v0 for longer.
Go imposes a cost on a v2 that I didn't consider.

v2.0.2