Update `svg_convertPngToBrands.sh':
- Rename function name from `svg_convertPngToBrands' to
`svg_convertPngToIcons'.
- Change the way size-specific images are stored in the working
copy. Now, size-specific images are organized inside
size-specific directories. There is one directory for each size
images are produced for.
- Start using inkscape to produce the base resized PNG image
instead of ImageMagick.