* Change favicon format from ICO to PNG
* Revert renaming `./favicon.ico`
Keep the backwards compatible file name `./favicon.ico` (though they will actually be in PNG format now).
* Add SVG template for creating favicons
Add `favicons.svg`, the template for creating the current PNG favicons, along with some helpful information about it in `favicons.svg.md`.
* Add source Inkscape SVG
Add source Inkscape SVG as an example of image tiddler in tw-com
Thanks to @cjrk and @cheigele for contributing their developer docs
(which can be found at https://github.com/cjrk/saa-tw).
By the way, I plan to remove the “creator” and “modifier” fields but
will keep a prominent acknowledgement for your contributions.