Patch release FBX2glTF v0.9.4

After a few months of being mired in other obligations, here is a new pre-release patch 0.9.4 of FBX2glTF. This is mostly a catch-up release for the various fixes that have accumulated:

• We now support 32-bit indices. By default, they are used for meshes with > 65535 vertices. The user can override this behaviour.
• @robertlong implemented the new extension KHR_materials_unlit: #61
• @davilovick found and fixed a problem in the way we transform normals, binormals and tangents: #48
• @davilovick also came up with a great fix for nodes with duplicate names: #51
• FBX2glTF will now (once again) compute normals. By default, we only replace spot-replace broken normals, but the user can tweak the conditions.
• @msfeldstein dragged the camera code into the modern age: #50
• Removed the broken and ornery code that tried to create fancy PBR textures from old-style Lambert/Phong type assets (but would often just create blank images). There is too much weird magic in those old models -- instead, FBX2glTF will now slam the material's diffuse texture (if it exists) into baseColor, and pick simple constants for metallicFactor and roughnessFactor.
• Bumped the embedded Draco version we depend on to 1.2.5.