Had to update the test scripts to handle the alpha channel, also I note
that all the hex tests are using CSS notation, not scratch notation
(which is 0x not #)
Also, fix a math error in `Color.rgbToHsv`.
Newly covered functions:
- `toRbgColorObject` from `util/cast.js`
- `hsvToRgb` from `util/colors.js`
- `rgbToHsv` from `util/colors.js`
- `mixRgb` from `util/colors.js`