add option to set background color, and always folow colorLight

[albertjan]

First of all thanks for the library!

This adds 3 things:

• backroungColor so we don't have to have an image with one color as a background.
• always use colorLight color light defaulted to "rgba(255, 255, 255, 0.6)" and it was impossible to change
• logoBackgroundColor so we can have a logo that has a see through background by setting it to `rgba(0, 0, 0, 0)

You've probably got this code stored somewhere else so I haven't made a new minified version and I haven't changed the node version. If you'd like me to do that let me know.

[StarNeit]

Hi @albertjan
I still can not change colorLight color to anything.
Did you find solution? thanks.