ANSI output used with non-ANSI terminals, NO_COLOR

[kornelski]

I'm running my Bevy projects via Sublime Text, which doesn't have a real terminal, only a super basic plaintext log.

The problem is that naga_oil uses ANSI colors on non-WASM targets unconditionally, without checking whether the terminal is compatible. In my case TERM is undefined, and I'm running std::env::set_var("NO_COLOR", "1") in main, but I still get ANSI color output that makes WGSL errors completely unreadable:

[robtfm]

i don't understand this well enough to fix it but a pr would be welcome.

[kornelski]

@robtfm submitted a fix in #103