Without conflicting with #86.

This is almost entirely trivial changes:

- Make dummy methods that should never be called either raise
  NotImplementedError or call self.fail() in tests.
- Standardize the no-coverage pragma
- Add a few pragmas where coverage varies across
  versions/implementations, mostly for the sake of tox (travis should
  hit them all).

- The bare import of '_zope_c_optimizations' prevented them from being
  used.

- After enabling them via absolute imports, they would fail due to
  http://bugs.python.org/issue15657.

Fixes #60.

Fixes #42

The decorator specifies the component name, so it does not have to be
passed in during registration. This in turn allows developers to define
component names once globally and use it everywhere, especially when
using ZCML where the name had to be specified a second time.

These APIs are still deprecated under Python 2.x, and still raise an
exception under Python 3.x, but no longer cause a warning to be emitted
under Python 2.x.

Code which uses the deprecated APIs will not work as expected under Py3k.

Instead of   ``implements``, ``implementsOnly``, or ``classProvides``,
prefer the equivalent class decorators: ``@implementer``,
``@implementer_only``, and ``@provider``.

We *can't* test the classAdvice stuff under Py3k.  Need to deprecate it
before the 4.0 release.