Add __all__ to all modules.issue153

Fixes #153

The items that went in each ``__all__`` are based on what is
documented:

 $ rg --no-filename 'import' docs/ -trst | tr -s "[:blank:]" | sort | uniq | grep zope
 >>> from pprint import pprint
 >>> from zope.interface import *
 >>> from zope.interface import Interface
 >>> from zope.interface import Interface, Attribute, implementer
 >>> from zope.interface import alsoProvides
 >>> from zope.interface import classImplements
 >>> from zope.interface import classImplementsOnly
 >>> from zope.interface import directlyProvidedBy
 >>> from zope.interface import directlyProvides
 >>> from zope.interface import implementedBy
 >>> from zope.interface import implementer
 >>> from zope.interface import implementer_only
 >>> from zope.interface import noLongerProvides
 >>> from zope.interface import providedBy
 >>> from zope.interface import provider
 >>> from zope.interface.adapter import AdapterRegistry
 >>> from zope.interface.declarations import Declaration
 >>> from zope.interface.declarations import InstanceDeclarations
 >>> from zope.interface.declarations import ProvidesClass
 >>> from zope.interface.declarations import named
 >>> from zope.interface.exceptions import BrokenImplementation
 >>> from zope.interface.exceptions import Invalid
 >>> from zope.interface.interface import Specification
 >>> from zope.interface.interface import adapter_hooks
 >>> from zope.interface.verify import verifyObject
 >>> import gc
 >>> import zope.interface

And also some personal judgement about what the public API is that I'm
more than happy to have reviewed.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/zope/interface/registry.py b/src/zope/interface/registry.py
index bba0267..3f1306f 100644
--- a/src/zope/interface/registry.py
+++ b/src/zope/interface/registry.py
@@ -39,6 +39,12 @@ from zope.interface.adapter import AdapterRegistry
 from zope.interface._compat import CLASS_TYPES
 from zope.interface._compat import STRING_TYPES
 
+__all__ = [
+    # Components is public API, but
+    # the *Registration classes are just implementations
+    # of public interfaces.
+    'Components',
+]
 
 class _UnhashableComponentCounter(object):
     # defaultdict(int)-like object for unhashable components