Remove unused files

[hypesystem]

lib/multicastresult.js and lib/result.js are not used anywhere in the code. They should be removed to reduce clutter.

These concepts may be interesting in the future, but half-finished versions shouldn't be lying around.
This is technically a breaking change, as they will be removed from the exposed interface.

[hypesystem]

At the same time, we could probably remove lib/constants.js from the list of files that are exported. No outside part needs to see these. It clutters the interface.