Stencil highlights (#701) * Initial work on stencil glows * Unbind SetStencilMode, not really needed, add clear with stencil support instead * Do custom blending to avoid overdraw and set render priority so outlines blend with eachother * Update shader * Bind pattern scroll scale to the shader and compile optimized shaer * Delete older highlight postprocess shader, actually bind clear with stencil support * Reduce number of iterations on thin lines * Remove pattern from being assignable in code, let it be done in material instead, * Use temporary depth-only rendertarget instead of clearing depth, there are effects that still depend on depth on screenspace postproecss stage, allow binding only depth * Remove standard shading code from highlight shader, doesn't need it at all * Put highlight shader on the same folder as highlightrenderer, put the old highlight shader on shaders folder so gamemodes that aren't updated don't break