What changed in EDuke32, build by build

This changes a constant inside the panning calculation from 256 to 255 (making e.g. panning 255 and 0 the same in the "San Andreas fault" sign in E1L5) and uses the correct reference wall for the "do panning correction?" conditional. Now, the problematic walls should look the same as in Polymost.

This makes the corrections conditional on where they appear in (under-, over-, white or mask wall).

Non-pow2 wall/mask drawing in classic introduced cases where walls are drawn "incorrectly" because they were constructed with the old behavior in mind. Polymer appears to "correct" for it partially, but doesn't cover all cases. Specifically, now we have: - E1L1 first inside secret room (5000, 50000): Polymer draws like Duke 1.5, classic now draws with an offset. - E3L2 near the vault (-20000, 25000): both classic and Polymer draw with offsets compared to Duke 1.5, but they're different! This means that more research is needed into what makes these two cases diverge, even though both have the same root cause. !!! Also, mappers should abstain from using non-power-of two textures on walls until this issue is resolved in a satisfactory fashion !!!

This properly fixes the unwanted vertical lines.