doc(transport.driver_base): Add docstrings

Also, renamed driver_base to base.py to be consistent with storage.

Change-Id: Iff59699a7c43341c2069823a8f39373c2d6b4760
Implements: blueprint transport-base
Implements base classes  for storage controllers

This patch follows (or should follow) the specs written in the v1
specification: https://wiki.openstack.org/wiki/Marconi/specs/api/v1

This patch deletes driver_base.py and adds base.py in marconi/storage
package.

Note: Most of this implementations will be tested in further patches
since there's no good way to test these base classes.

Implements blueprint storage-base

Change-Id: Iefa6374635fcf9dd9fc60417d8ed5c306bbc619a
Merge "Implements base classes  for storage controllers"
Use issublcass instead of isinstance

StorageBaseTest should check for issubclass instead of isinstance since
the driver / controller instances are not yet created at that time.

Fixes bug 1154690

Change-Id: I12a76305045cd7dfb8c98ece97e9e6c02e0b7622
Decentralized configuration.

The configuration is based on oslo-config, while this module lets
each module which want to be configured define the options it need
by itself, and get the limited access to those config variables.

Implements blueprint config-module

Change-Id: Iffbb859da0cb5fb8434bc439320bf6c20f9d39b5
Merge "Decentralized configuration."
fix(tox): Address warnings

* Remove "bash" from command string in testenv:pep8 to stop it from
  complaining about referencing something outside the virtualenv.
* Add missing pyflakes dependency

Change-Id: I10ae6dba764b4e7d7fcb9aef3f8d84b30ba1c773