Issue LIBCLOUD-417: Add support for more EC2 Elastic IP Address operations.

Add support for:

DisassociateAddress
ReleaseAddress
AllocateAddress

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Update changes.
For consistency and accuracy, rename "ex_associate_addresses" method in the
EC2 driver to "ex_associate_address_with_node".
Pep8 and fix ex_owner handling in the list_images method.
docs: Update upgrade notes.
Fix ex_list_publis_ips in the CloudStack driver so it works with basic zone.

Part of LIBCLOUD-418.
Don't run "docs" target as part of the default tox run.
Import LockTimeout before trying to catch it.

If lock.acquire raised any sort of exception, a NameError would
trump it because the __enter__ method was trying to catch
lockfile.LockTimeout, which wasn't imported.

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Fix a test.
Add new "lint" target to tox, flake8 fixes in the whole codebase.
Fix a test.
Run lint step on travis-ci.
Issue LIBCLOUD-358: Add compute driver for CloudFounders CloudFrames.

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
pep8 fixes.
Update changes.
Update travis config.
Add git pre-commit hook script for running flake8 on modified Python files.
docs: Document how to install a pre-commit hook.
Remove unnecessary contribute.
docs: Update CI section.