[pygame] array_colorkey / colorkey blit inconsistancy

["Lenard Lindstrom" <len-l@xxxxxxxxx>]

A colorkey blit uses the full surface alpha for the opaque areas of 
the source surface. Yet array_colorkey ignores full surface alpha and 
just returns 255's instead. To be consistant with colorkey blit 
array_colorkey should use surface alpha as well. This would make it 
easier to use the resulting array in shadow effects.

The change is small an I am willing to submit a patch if it is 
accepted.

Lenard Lindstrom
<len-l@xxxxxxxxx>