Added model group support, you can now have multiple meshes in one export.
Removed OBJ and mesh replace export options.
Mesh replace didn't work, might get added again in the feature.
OBJ needs to be rewritten as well to support the multiple meshes, and Unity now has model export options in engine.
Version 1.8.0+ is now only supports Unity2018.3+.
[MA_TextureAtlas] Updated export window to use scriptable asset export presets. The option to wrap uv's (default = true). Bigfixes and code formatting.
Fixed gray texture on export bug, it was caused by the texture scale function (during upscaling), right now it's required to have the texture dimensions be a power of 2 width/height.
Optional OBJ/PNG/sprite export options.
Chanaged readme.
TODO: Cleanup export code. Make proper scale options (bilinear & point).
