Changed divisor to float to make halfdim setting Python 2 and 3 compatible
Changed divisor to float to make halfdim setting Python 2 and 3 compatible

Eric89GXL/vispy,ghisvail/vispy,drufat/vispy,Eric89GXL/vispy,ghisvail/vispy,michaelaye/vispy,ghisvail/vispy,michaelaye/vispy,drufat/vispy,michaelaye/vispy,drufat/vispy,Eric89GXL/vispy