Add an additional size for highest possible accuracy

[otto802]

I get that this is mostly a flag icon library and for that purpose it's great. However we were trying to use this for sports related software, for instance for larger screen displays and even TV/livestream coverage. We quickly found out that some flags are not accurate for that purpose. For instance the number of stars of the US flag and the relation of the blue star background, the wrong order of colors at the Palestinian flag, etc. There where more examples, which cause quite some troubles ;-)

For the purpose of "icons" the sizes and accuracy are ok, but maybe it would we worth adding an additional size which reflects ideally the highest possible accuracy of flags. We've tweaked/fixed some icons by ourself for our purpose. Happy to share those here!