Regenerate zope.interfaces stubs

[kedder]

And reapply all changes that we've manually made.

Fixes #102

[Daverball]

I recommend running stubtest which is included as part of mypy to automatically detect discrepancies between the stubs and the runtime package, that way changes can be done much more incrementally in lock step with zope.interface, without being forced to regenerate the stubs from scratch.

You might also consider to adopt the typeshed versioning scheme, which uses the same version as the base package (i.e. zope.inteface) and uses a fourth number to differentiate incremental changes for the same zope.interface library version.
Although in that case you might try to repurpose stubsabot from typeshed to notify you when a new zope.interface version conflicts with your stubs (and otherwise bump the package version and publish a new version to pypi).

Although it's probably easier to just use a weekly CI run with stubtest and stick with the old versioning scheme, even if it makes it more difficult for people to know which version of zope.interface the stubs are compatible with.