Rename colors.js to color.js to match the component name.

Signed-off-by: J. Renée Beach <splendidnoise@gmail.com>
Fixed color.js test failures. Refactored the color tests to return multiple cases so that we can pinpoint the exact type of contrast error or errors.

Signed-off-by: J. Renée Beach <splendidnoise@gmail.com>
Added test for non existing image and external image
Small typos in comments
Merge pull request #226 from quailjs/bug-colorjs

Test fails in color.js

My comment about the try/catch is trivial. The new tests are good additional coverage. I need this in dev so I can continue with some refactoring.