Getclosestcol
getclosestcol <RETURN> <color> <limit>
Finds the closest palette index to the <color> given.
<color> is encoded the same as PROJ_FLASH_COLOR
<limit> is the index of the last palette color that should be considered. Use 255 for the whole palette, 254 to exclude the transparent color, 239 to exclude Duke 3D's fullbrights, etc.