Adjusted the number of pixels when upsampling to not lose any data.
Adjusted the number of pixels when upsampling to not lose any data.

When upsampling, if the scaling ratios cause the number of pixels of the
output image to be a fraction of a pixel, we round up so we don't lose any
data.

Before, we were rounding the number of pixel to the closest integer, but that
means that we could lose up to half a pixel worth of data.

This shouldn't have much of an impact on the output image, especially when
using nearest neighbour.

ecometrica/gdal2mbtiles