Allow logo option to be an array

[mikroware]

The favicons library seems to support an input array of sources. As far as I have read this is pretty useful for generating different icons for different sizes. E.g. to have a slightly different logo when resized to 16x16 and a more detailed one above 100x100 for example.

source = 'test/logo.png',                     // Source image(s). `string`, `buffer` or array of `string`

favicons(source, configuration, callback);

[brunocodutra]

Sounds like a good idea, thanks for the suggestion