Improved parsing of `docker ps`

This will fix, e.g. parsing of commands with two spaces in them.
More reliable command matching.

If docker command is e.g. `sh -c 'cd foo && ./bar'`, then
`docker ps` will show the command as `sh -c cd foo && ./bar`.
Handle this case when matching on container commands.
Add Chefspec matchers
Merge pull request #86 from intoximeters/chefspec-matchers

Add Chefspec matchers
Merge branch 'master' of github.com:bflad/chef-docker
Add Ubuntu support to cgroup recipe
Rename execution_driver and storage_driver to match Docker terminology
Yak shaving: rubocop fixes for %w literals and extraneous .to_s
s/execution_driver/exec_driver/g
Bump version to 0.32.0 for continuing development and CHANGELOG 0.32.0 and 1.0.0 so far
Initial Vagrantfile support for AWS/Rackspace
Add -e flag for execution driver, closes #84
CHANGELOG entry for #84
Make -rm the default for docker build, closes #78
Add -f flag to docker rm to force removal of running containers, closes #82
Add -f flag for docker rmi to force removal of images
Add a -G option to specify the group which unix sockets belong, closes #81
Add DOCKER_RAMDISK environment variable to make Docker work when the root is on a ramdisk, closes #83
Prefer long flag names when using cli_args
Use double dashed arguments on CLI, closes #80