cleanup: draw_rect always ortho, has unused members

[jarikomppa]

draw_rect has functions to set the ortho mode as well as member variable to set it on, but since the ortho mode is always set in the parser, these are not needed and could be removed.

[dj2]

In VkScript the EnableOrtho call is conditional on the ortho flag in the draw command. This calls either EnableOrtho or EnablePatch. So this needs to be maintained.