Extend some meshing modules to 2D

This MR extends the functionality of NekMesh in 2D:

• The cyl module now works in 2D. The cylinder center can now be passed as a parameter, instead of always being at the origin.
• The boundary layer module is extended to Quads.
• A new module was created that generates curved edge information in 2D based on a prescribed function y=f(x).