[Enhancement] Read SKYDEFS when searching for used textures

[electricbrass]

Currently, using WTexScan on a wad with SKYDEFS and UMAPINFO lumps as below, and which does not otherwise use SKY2, will result in SKY2 being left out of the list.

{
  "type": "skydefs",
  "version": "1.0.0",
  "metadata": { },
  "data":
  {
    "skies":
    [
      {
        "type": 2,
        "name": "SKY1",
        "mid": 100,
        "scrollx": 0,
        "scrolly": 0,
        "scalex": 1,
        "scaley": 1,
        "fire": null,
        "foregroundtex":
        {
          "name": "SKY2",
          "mid": 100,
          "scrollx": 0,
          "scrolly": 0,
          "scalex": 1,
          "scaley": 1
        }
      }
    ],
    "flatmapping": null
  }
}

map MAP01 {
    skytexture = "SKY1"
}

[aJynks]

this would be a great addition, but mapinfo also has a sky texture definition. Maybe even more (I do not use other formats personally, so do not know)

Work Around

I have been placing a small control sector in map01 with all my sky textures in it. That way they are added to the final output wad and the umapinfo setting no longer crashes out by the sky not actually being included.

[electricbrass]

It already reads the skys from mapinfo