Improve the way the absolute layout information of elements are computed.
Begin work on improving the way clipping rectangles are calculated and stored for each element.
Simplify the rendering of elements.
Cleanup.
Have elements be marked as needing clipping or not.

This is going to be used as a rendering optimization in the future.
Cleanup.
Reorganization.
A small optimization to rendering.
A small optimization to the renderer.

This optimization prevents some unnecessary scissor modifications.
Improve the way the text cursor is drawn.
Cleanup.
Another small optimization to prevent unnecessary scissor modifications.
A small change to the way invisible elements are handled by the renderer.
Initialize a member variable in Renderer.
Optimization to the way opacity is handled.
A few changes to the renderer to allow implementations to implement some optimizations a little easier.
Fix a rendering clipping bug.
Rework the renderer to make it easier for implementations to optimize blending.