Make end-user modules accessible from top level

There are several modules that end-users are expected to be
using--connection, profile, exceptions, and utils--which could be made
slightly more accessible by having them available in the top level
`openstack` namespace. This change proposes importing `from openstack
import <x>` in openstack.__init__.py so that end-users can do `import
openstack` and then work from there.

Nothing more than the typical end-user entry points are to be exposed
from there, so if you need to get the server resource you still need
to do `from openstack.compute.v2 import server`. Additionally, we should
continue documenting and using in tests everything in the `from
openstack import <x>` format ourselves as this is merely a convenience.

Change-Id: I24a7ce3636b18287fcb2246fbdfa9f8b6767f323

openstack/__init__.py

@@ -0,0 +1,16 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from openstack import connection  # NOQA
+from openstack import exceptions  # NOQA
+from openstack import profile  # NOQA
+from openstack import utils  # NOQA