Enable color on Travis CI and AppVeyor about crayon

[gaborcsardi]

How about forcing it with an environment variable?

[krlmlr]

I'd prefer if crayon just worked. Otherwise users would have to clutter their .travis.yml and appveyor.yml.

Use case: ropensci/tic#5.

[gaborcsardi]

On Travis the output is written to files, and then if you read these files programatically, or download them from Travis, they will contain the ANSI characters.

If you need to turn on colors for testing, you can always do that with options(crayon.enabled = TRUE); options(crayon.colors = 256).

[gaborcsardi]

I am just afraid that turning it on will actually cause confusion.

[krlmlr]

I'd like to use color to highlight terminal output, but I can work around for my particular use case. I see how this can break in unexpected ways.

Maybe if we had a force = FALSE argument to each style function?

[krlmlr]

No, that won't work either... Thanks anyway for considering.