add support for specifying time formats

[m4rch3n1ng]

add support for specifying a format for timestamps (--time-format) in --long mode. the formats are inspired by the git implementation.

i was unsure of what flag to use, but since you used --time over --date, and therefore --time was already taken by something else, i chose the more explicit --time-format flag.

i chose to add the formats iso, iso-strict and short, the latter two strictly following their implementation in git, with iso dropping the time zone specifier entirely (since the time zone is local-only anyway), but i made it so you should be able to easily expand to more options if needed.

the old format is still the default or can be explicitly specified with --time-format default. i would personally consider using the full year instead of only the last two digits, but that would mean recreating a good number of screenshots in the readme, so i didn't

i do not know rust well enough to know how or even if to best implement unit tests, so i did not.

say when you want me to change anything. ty.

[solidiquis]

This looks great! Thank you. For future reference please refer to CONTRIBUTING.md for instructions on how to go about creating a new PR.

I won't be able to review this until the end of the week but upon a quick glance I don't think this will require any unit-testing.

[m4rch3n1ng]

oh i'm so sorry i actually read the CONTRIBUTING.md, but i completely missed that note at the end...

i thought about opening a seperate issue beforehand, but since i wanted to write some rust anyway and it was like a 10 minute thing i just went for it and if you were to reject it or want me to completely rewrite most of it, it would not have really mattered

thank you and take your time

[solidiquis]

No biggie! :)

[solidiquis]

Hey I'm so sorry for getting back to this so late—work and personal life has been quite hectic. So by and large these changes look good and I'd like to include this as part of the next release. If it's not too much trouble, would you be able to request to merge these into the v3.0 branch instead of master? You might have to do some small refactors as I just decoupled the node module from all of the rendering logic.

The formatting of the timestamp has been moved here! Again sorry for getting back late. Let me know if you have any questions!

[m4rch3n1ng]

done i think

[solidiquis]

Thank you! Will include it in v3.0 which I'm aiming to release before next week :]

[m4rch3n1ng]

ty, looking forward to it...