Support color schemes

[lread]

New :color-scheme option specifies iTerm format color scheme. See changes to README for usage.

In support of this change, scheme-able color support added for:

• :cursor (cool alpha trick turfed in favor of color scheme support)
• :cursor-text - color of text when cursor is over text
• :background - screen background
• :foreground - default text color

Also:

• noticed membrane.term was crashing when I tried https://github.com/sharkdp/bat. Added support for 24-bit colors.
• made some very minor clj-kondo recommended cleanups

Notes:

• Minimal, but adequate, error handling included for iterm color scheme loading.
• Terminal resize functionality unchanged but you'll notice that background color does not grow to larger size.
• I made some guesses on how to use skia, some of them were likely naive.

Closes #1

[lread]

@phronmophobic, my first crack at color schemes, very happy to make changes, lemme know whatcha think.

[phronmophobic]

Added support for 24-bit colors.

What are the changes for 24-bit?

[phronmophobic]

noticed membrane.term was crashing when I tried https://github.com/sharkdp/bat.

I couldn't reproduce a crash. If you have a way to reproduce, can you file an issue?

[lread]

Added support for 24-bit colors.

What are the changes for 24-bit?

I really should have put this in a separate PR instead of sneaking it into this one. Sorry about that! The change was very minor. We just needed to understand that asciinema/vt can also return an [r g b] vector representing a 24-bit color.

[lread]

noticed membrane.term was crashing when I tried https://github.com/sharkdp/bat.

I couldn't reproduce a crash. If you have a way to reproduce, can you file an issue?

Crash might have been strong wording. It just died with a normal JVM exception. I'll file an issue with a repro.

[phronmophobic]

Sounds good. Merged. Thank you!