GD::Map::Mercator TO DO

- add convenience functions:
	- fill($lat, $long, $color): fill region containing $lat, $long with $color
	- north_america($width, $height) return N. America map of specified dimensions
	- south_america($width, $height) return S. America map of specified dimensions
	- europe($width, $height) ditto Europe
	- asia($width, $height) ditto Asia
	- africa($width, $height) ditto Africa
	- (whence Australia/New Zealand ?)
	- usa($width, $height) ditto USA
	- maybe other countries

- fix for asia data (-riv, -cil is all f'ed up)

- finish keep => { set => list } support

- fiddle w/ smoothing borders for visualization purposes
	- return image map of relevant parts