Latex backend: optimizing cell rendering.
- Fix cell walls height to correspond to rewrite height. Right now cell walls height = 2*LHS height and rewrite line is always in the middle. Requires learning some more ticz.
- Optimize cell width to be based on real cell height, not on maximal one. Requires rendering each long cell 3 times: one time without wrapping, second time wrapped, assuming maximal cell height. The 3-rd rendering - wrapped, assuming height measured from the 2nd rendering.