Allow changing character outline and fill color

[sanand0]

Currently, Dee and Dey are in black and white. Zoe is in color.

Change the API to allow re-coloring the SVGs -- ideally without the author having to create new images. Color maps may be a possibility.

[sanand0]

Note from @pratapvardhan

• You can apply filter: css on svg tag.
• You can apply this to SVG only. It does not work on SVG's (image, or g) tags.
• Which means, we can color any complete character within SVG to one color.
• If SVG contains multiple characters, and want to have different colors, we can't really us this. (Can't color different parts of bod separately too)
• This shows you can get any hex color using a filter. CSS filter generator to convert from black to target hex color.