[REQUEST] Edge merging in exported models

[ScoreUnder]

Use case

Editing meshes with disconnected faces in 3D modelling tools is quite finicky and this could be made easier by exporting with merged edges.

Solution

Export with edges merged by default, where applicable (continuous UVs, same materials, etc?)

Alternatives

• Pre-export tools to modify meshes
• Deal with the frustration when tweaking output manually, I guess?

Additional context

Based on #169 to keep the requests separate as they are likely to be resolved at different times