Add support for breathing between colors

[tylerszabo]

Feature request

Summary

Add --breathe mode to smoothly transition between 2 (or possibly more) colors.

Caveats

• In testing the "transition" mode doesn't seem to honor the initial color set which limits the ability to have the controller handle moving between the colors.

• Gigabyte's SDK doesn't directly support such a mode so implementation will require running a daemon to actively transition.