Use ||= in Shape#bbox to avoid a warning. Also shorter.
Use period for Math functions instead of paamayim nekudotayim.
Allow named parameters for circle().
Allow named parameters for cone().
Add magic_shape_params and implement circle's and cone's named parameters
with it.
Allow named parameters for cylinder().
Add TODO for cone().
Swap parameter order for cylinder().
Allow named parameters for sphere().
Allow specifying defaults in magic_shape_params.
Defaut cone()'s dh param to 0.
Allow named parameters for torus().
Allow named parameters for reg_prism().
Allow named parameters for reg_poly().
Rewrite pedestal example with new features. (Also, fix use of radians.)
Use new features in README.md example
Wrap C++-level Transform.move etc. with trivial Ruby methods.

C++-level methods now have an underscore prefix.
Wrap params nicely for Transform#move and #scale.
Allow 2D transforms in Transform#move and #scale.
Explicitly specify params for rotate and mirror wrappers.