Allow editing studio model data

[SamVanheer]

Studio models have a lot of data and it can be difficult to edit the usual way. Add options to edit the various parts of studio models.

• Header data

• [x] eye position
• [x] min & max bounds (character bounding box)
• [x] bbmin & bbmax bounds (clipping bounding box)
• [x] model flags

• Bones (skeleton)

• [x] ~Add~
• [x] ~Remove~
• [x] Edit
• [x] ~Move~

• Bone controllers

• [ ] Add
• [ ] Remove
• [x] Edit
• [ ] Move

• Hitboxes

• [ ] Add
• [ ] Remove
• [x] Edit
• [ ] Move

• Attachments

• [ ] Add
• [ ] Remove
• [x] Edit
• [ ] Move

• Sequences

• [x] ~Add~
• [ ] Remove
• [x] Edit
• [ ] Move

• Sequence groups

• [x] Merge (automatically performed on load)

• Textures

• [x] ~Add~
• [x] ~Remove~
• [x] Edit
• [x] ~Move~

• ~Skins~

• [x] ~Add~
• [x] ~Remove~
• [x] ~Edit~
• [x] ~Move~

• ~Transitions~

• [x] ~Add~
• [x] ~Remove~
• [x] ~Edit~
• [x] ~Move~

• ~Body parts~

• [x] ~Add~
• [x] ~Remove~
• [x] ~Edit~
• [x] ~Move~

• ~Meshes~

• [x] ~Add~
• [x] ~Remove~
• [x] ~Edit~
• [x] ~Move~

[SamVanheer]

Some parts of a model are too difficult to edit in its compiled form. For those cases the source files should be modified instead.