Mesh support / robustness

[BIackthorn]

So I noticed in XLB we have some strong STL mesh assumptions, such as the number of triangles = the number of vertices and the triangle indices map directly to the vertex order. If we do any mesh processing like removing duplicate vertices or if we want to support other types of meshes, this will break.

[hsalehipour]

hi @BIackthorn , is this issue fully addressed in the this PR #102 ?