#52 Fix PCX reader 1 bit color, 1 bit plane

[Ti-R]

Fix PCX reader 1 bit color, 1 bit plane

Bug: The PCX with 1 bit color and 1 bit plane was not correctly loaded, problem with the width, must not be compute, but BPS must be use instead. And no padding need at the end of the line.

Thank for OpenIL community, I use it for years, great library!

Ti-R