- Travis CI inits and fetches Git submodules so those steps are unneeded (let alone updating the submodules).

- Caching the entire virtualenv in Travis CI has proven to cause issues, caching just pip's cache directory.

- Use privileged container instead of just adding the sys_admin capability (the latter has been shown to be cause unrelated issues).

# Conflicts:
#	.travis.yml
#	README.rst
#	molecule.yml
#	tests/playbook.yml

# Conflicts:
#	tests/playbook.yml

# Conflicts:
#	defaults/main.yml
#	handlers/main.yml
#	molecule.yml
#	tasks/main.yml
#	tests/playbook.yml
#	vars/main.yml

- Remove mention of tests/requirements.yml from the Requirements section in the README, relevant only for testing.

- Move DH params test from Testinfra to post_tasks to workaround a limitation when running tests with Docker.

- Added submodule init and update to Travis CI.