Big documentation and structure updates

- Split math into fdmath package
- Rename waveguide into _2d _3d and _cyl variants
- pdoc-based documentation

meanas/fdfd/__init__.py

@@ -1,2 +1,17 @@
-from . import solvers, operators, functional, scpml, waveguide, waveguide_mode
+"""
+Tools for finite difference frequency-domain (FDFD) simulations and calculations.
+
+These mostly involve picking a single frequency, then setting up and solving a
+matrix equation (Ax=b) or eigenvalue problem.
+
+
+Submodules:
+
+- `operators`, `functional`: General FDFD problem setup.
+- `solvers`: Solver interface and reference implementation.
+- `scpml`: Stretched-coordinate perfectly matched layer (scpml) boundary conditions
+- `waveguide_2d`: Operators and mode-solver for waveguides with constant cross-section.
+- `waveguide_3d`: Functions for transforming `waveguide_2d` results into 3D.
+"""
+from . import solvers, operators, functional, scpml, waveguide_2d, waveguide_3d
 # from . import farfield, bloch TODO