TSA: TH06: Never skip PNG splitting based on the original PNG's pixel format. [V]
TSA: TH06: Never skip PNG splitting based on the original PNG's pixel format. [V]

This fixes two problems:

• title04_a.png in the static English patch is a 256-color grayscale
  image. This fact triggered an image skip, which always crashed for
  the alpha image since we previously set `fr->rep_buffer` to a nullptr,
  but then still unconditionally memcpy()'d that.

• When previously using a thcrap translation patch on top of Emarrel's
  Retexture Pack, the latter's RGBA images also triggered an image skip.
  This meant the alpha image for our patch's image was never generated,
  leading to textures with a weird combination of the Retexture Pack's
  alpha channel and the thcrap patch's RGB channels.

… Actually, Emarrel's Retexture Pack nicely demonstrates that TH06 does
indeed support RGBA PNGs just fine. The pack still includes the _a PNGs
with separate alpha channels, but if you zero out the Name2 field in the
ANM, the game will just accept RGBA PNGs together with their alpha
channel. (And there's no reason it shouldn't, TH06-TH09 are pretty much
identical in how they load textures through D3DX.) ANM modding simply
wasn't there yet in 2008 to consider this option, I guess.

This still does not mean that we'd better get completely rid of the PNG
splitting code though. Sprite-level image patching still needs to work
on top of the original split PNGs, which implies some sort of channel
splitting or merging code.
So Bruno's 2016 work wasn't all for nothing.

thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap