BMP translator flips some bitmaps when it shouldn't.
|Reported by:||mmu_man||Owned by:||nobody|
|Has a Patch:||no||Platform:||All|
Our BMP translator assumes all BMP data are bottom-to-top, but actually it's possible to have the data top-to-bottom, in which case the height field is negative. The comments in the code already includes a TODO about it.