Mesh Batch Cache: Move index buffer range hack to be more local

Mesh Batch Cache: Refactor: Again

- Use Extract naming convention to name extract functions that fill vbo/ibo
- Separate extract functions into separate file (for clarity)
- Make simpler iter loops to avoid as much overhead as possible
- Separate loose elements looping functions to avoid iteration complexity
(unfortunately this makes the code more verbose).
- Some iter functions are threadable and tagged as such.
- Add multithreaded iteration for extract functions that supports them.

GPU: Elements: Put back index tracking in index_buf_set_* functions

There is no threadsafe way of filling the IBOs. So keep filling them
simple and track used indices length.

Mesh Batch Cache: Fix threading issue with element buffer objects

Some elements indices can be written by multiple thread at once and
since setting an element is only garantee to be atomic for single verts,
we cannot reliably use GPU_indexbuf_set_line_* in this case.

To avoid this, we create another iteration for the problematic IBOs

Cleanup: Remove Printf

Merge branch 'tmp-batch-cache-cleanup' of git.blender.org:blender into tmp-batch-cache-cleanup

Mesh Batch Cache: Fix some threadsafety issue with indices buffers

Mesh Batch Cache: Fix some threadsafety issue with indices buffers

GPU: Make small float normal compression functions inlined

Mesh Batch Cache: Fix bitmap test for loose verts

Mesh Batch Cache: Add debug timer

Cleanup: Mesh Batch Cache: Rewrite iterations to prepare for multithreading

Mesh Batch Cache: Speedup: Move the prev edit edge hack for edit uv...

and move it to the only function that needs it: mesh_edituv_data_iter_edit.

Mesh Batch Cache: Speedup: Remove the need for memset in index buffer init

Instead of setting the whole IBO to restart index, we only set the restart
indices when we encounter a hidden elem.

Cleanup: Mesh Batch Cache: Remove old unused code

Cleanup: Silence warnings

Mesh Batch Cache: Refactor: Fix subdiv UV edge highligh in vert select mode

UVEdit: Support Mesh eval cage selection

- Select Vert / Edge / Face support
- TODO : Rect / Lasso / Circle / Loop

Mesh Batch Cache: Refactor: Fix lnor & vnor display

Mesh Batch Cache: Refactor Part 6

Add back subdiv facedot correct position.