Added export option to reuse vertex indices (no UI control yet).
Added export option to indent formatting for glTF2 and DAE (no UI control yet).
Added export option to turn on or off strict formatting of floats by using fixed decimal places (no UI control yet).
Added support for DAEExporter (no UI control yet).
Added support for specifying custom prefix name for exported files (no UI control yet), empty will default to using the exporter's preset, which is declared when _options.Validate("preset") is called.
ExportModelOptions now supplies FloatFormat property, GetBaseName, and GetTextureName, so that all exporters are consistent.
Switched all cases of manual path combining with string formatting to Path.Combine.
Fixed ModelPreparerExporter making tiled textures powers of two, even when exporting to single texture (which would just take up space needlessly).
Replaced instances of File.Open with File.Create when the goal was to write a new file. File.Open won't reset the file size to zero.
OBJ format now outputs $"o object{i}" for each entity in the model.
OBJ and PLY now output vertex definitions in reverse order, meaning face definitions no longer need to be defined in reverse order.
All exporters now correctly track if a shared texture has already been exported.
glTF2Exporter now outputs .gltf file using DOM-based schema objects and Newtonsoft.Json serializer.
General exporter refactoring. Intended for when a ModelExporterBase class is eventually added.