glTF2 skin support and PSI parser fixes

[trigger-segfault]

• Fixed PSI failing to parse in release builds because of a commented out line.
• Fixed PSI\x01 models failing to load, and also failing to handle skinning.
• PSI sub-models now append their mesh name in the tree view.
• Fixed packed textures not being exported correctly when attach limbs was turned off.
• glTF2 now supports exporting skinned models with animation (using joints/skins).
• Fixed glTF2 error that could occur when exporting HMD models with shared vertices.
• Fixed attachable vertices not always exporting correctly if they were assigned to an empty model.
• PSX TMD IDs are now assigned based on the object ID and not the model index (which should be more correct, considering hierarchy uses object indices too). This means TMD IDs can be assigned out of order again. :/
• PSI default frame rate can now be changed in settings.json using "advancedBFFFrameRate". The default is 30, which works for Frogger 2 and Chicken Run. The other recommended value is 60, which works for Action Man 2.