- Splits Hoppy into four packages with different licenses:
  - generator: The code generator.  AGPL-3+.
  - std: Bindings for standard library classes.  Apache-2.0.
  - runtime: Runtime support for Haskell bindings.  Apache-2.0.
  - docs: Documentation, currently the user guide.  AGPL-3+.

- The stdlib header files now live in the std package and std is aware of
  their location, so passing CXXFLAGS=-I$(generator --get-include-dir) to
  make is not needed any more.

- Also as part of the split, iterators are now in the std package, and are
  no longer class features.  They also have nice method names now.

- Makes 'classAddCtors' and 'classAddMethods' public in Spec.

- Makes various enhancements to the user's guide.  Partially addresses the
  inconsistency of using both 'cpp' and 'lib' for the C++ side of bindings.

- Removes some stale dependencies from the generator.

- Fixes the pre-commit to recognize the different licenses, and show the
  correct list when leading tabs are found.