Xeltalliv/simple3D: fix bugs with transform direction block, model importing, invalid mesh drawing

[Xeltalliv]

• If transform direction from to has to directly use 1 existing matrix instead of creating a new one, it ends up zero-ing out 13th-15th (12th-14th) elements of it which are responsible for offset. This block wasn't meant to have any side-effects on the input data. Example https://github.com/TurboWarp/extensions/commit/b1af7dbe10def059bb6829d183d54c8d82d82e4f
• Mesh without vertex positions is considered valid for drawing and trying to draw it throws an error. Example https://github.com/TurboWarp/extensions/commit/a4c328f76ded1c649d66dcb267be6a3bbab804e3
• In OBJ importer, material colors do not work, because extension is looking for Ka (ambient) tags instead of Kd (diffuse) tags. Example https://github.com/TurboWarp/extensions/commit/b13092434f6fe01806a172f3416a0c09e47a7fe4
• In OFF importer, default value for red was missing. https://github.com/TurboWarp/extensions/commit/b13092434f6fe01806a172f3416a0c09e47a7fe4
• In OFF importer, colors are not parsed correctly. They can be provided as integers 0 to 255 or as floats 0.0 to 1.0, but currently everything is treated as floats. That is why OFF example from the Wikipedia doesn't work. Can be tested in this. https://github.com/TurboWarp/extensions/commit/8343bd00b49b67205f223598a94ebcc6c17fea53
• import from file transform is incorrect, because it doesn't copy values before modifying them, so ends up using already processed values mid-computation for the remaining ones. In the past I had a reduced copy of m4 library in the WebWorker, so it worked correctly, but then I incorrectly simplified it and only tested scaling which still worked correctly. Example https://github.com/TurboWarp/extensions/commit/d008f028a62b6c09738a83a519c10c76297a5862

The example projects weren't made for this PR and are the part of the new documentation.