Avoid continuous forking and added FIGlet rendering using a custom font

[MIvanchev]

Hey @coryfklein, I propose the following changes which avoids forking sleep & date 30 times per second and in fact doesn't use sleep and date at all. I also added an option to support FIGlet rendering with a fancy font I created for the stopwatch. You can use it through sw -f stopwatch.flf. The problem is that the set of changes introduces a dependency on Bash 5.0 because this is when EPOCHREALTIME was introduced.

My intention is to turn sw into the standard *nix CLI stopwatch tool because there is currently no alternative. This would require creating a well-formed package including for example a man page..

[coryfklein]

Hey @MIvanchev ! Thanks for submitting this PR. I appreciate your interest in contributing to sw. I currently don't have the time for any meaningful development on the tool, so I've added you as a collaborator. As a test to make sure I did it correctly, go ahead and merge this PR yourself; let me know if that doesn't work and I can try to tweak the permissions. Feel free to add whatever you see fit to sw.

[coryfklein]

Closing from inactivity. Happy to reopen later.

[MIvanchev]

Terribly sorry @coryfklein, I have missed the messages due to bad email filtering, let me get back to you ASAP. I'm really very sorry.

[coryfklein]

No worries! I'll reopen it and you can merge it when you're ready.

[MIvanchev]

Right, I'm just surprised how this could've happen, I usually answer within minutes 🥲

[coryfklein]

Hah well then you're far ahead of me. I only just got my Github notifications correctly configured such that I will even know when folks submit PRs on this repo...