helper method for finding and matching triangles. fixed some codependent indices in patch index buffer computation.

This reverts commit 6ee50809.

Added 12 Patch start

(when a triangle can't find all three adjacent vertices: don't create new edge points, keep indices for old triangle. Still creates holes though, since vertex points are moved anyway.)

normal fix

some changes to Mesh entry handle

precompute new indexbuffer
- new vertexbuffer first contains vertex points in order of original vertices in vertex buffer
- new vertexbuffer then contains edge points that were created in order of edgeIndices