docker bugfixes: trim whitespace around list param elements, handle list params being coerced to int or long type

Useful for development environments.  Setting these options to true
allows you to `docker attach` to a docker container started with
ansible.

The new present state just makes sure that a container exists, not that
it's running, although it get started one creation.
This is very useful for data volumes. This also changes the old
present, now running (default) state to only create the container if
it's not found, otherwise it just get started.

See also discussion on mailinglist:
https://groups.google.com/forum/#!topic/ansible-devel/jB84gdhPzLQ

This closes #6395

All modules should be using /usr/bin/python in the shebang as ansible_python_interpreter processes this (see FAQ).
Fixing for standardization purposes.

raise errors when omitted, updated changelog with new modules.

When using repositories other than the main one at docker.io, the image name contains the repo name (which itself contains ":" as a separator between domain and port). We don't really care about it here, so just get rid of it before looking at the image name.