Adds a way to customize the color of the svg before download.

How to:

1. Find the icon you want to download
2. Click the 'find' icon
3. On the top right there should be a new 'Custom color' button. When clicked a prompt will appear where you can enter a 3 or 6 char hex code (e.g 'FFFFFF').
4. After clicking OK the new color should be reflected in the little color preview box. (Note that the icon itself can't be updated)
5. When you now click on the "Download colored SVG" it should prompt you to download the SVG, with the new color reflected in the file name.

I publish my userscripts under an MIT license in hopes they are helpful to others. I don't have a ton of time but I do try to keep these updated when I can. If something broke or if you have any suggestions, please don't just leave a bad review, leave some feedback (or even better, a pull request via github) and I'll take a look when I get a chance. Let's improve these together. Thanks all!