Standardize color response format about color-thief

[jfsiii]

My preference is that getDominantColor's response format change to an array [num, num, num] to match createPalette

This make CSS strings as easy as:

var dominant = getDominantColor(image); // [1, 11, 111]
var CSS = 'rgb(' + dominant + ')';      // rgb(1,111,111)

{r: num, g: num, b: num} may be more explicit but it doesn't have the toString benefits shown above and you'll still have to pick out individual elements whether using an array or an object.

For example:

var obj = {r: 1, g: 11, b: 111}
if (obj.r) { /* do something */ }

var arr = [1, 11, 111];
if (arr[0]) { /* do something */}

var r = arr[0], g = arr[1], b = arr[2];
if (r) { /* do something */}

[lokesh]

Updated with your pull request.