Get rid of more wildcard imports and add boilerplate to more modules

This commit cleans up the following module categories:
* messaging
* inventory
* crypto
* commands
* clustering
* cloud/webfaction
* cloud/docker
* cloud/digital_ocean

lib/ansible/modules/cloud/digital_ocean/digital_ocean_domain.py

@@ -1,20 +1,13 @@
 #!/usr/bin/python
 # -*- coding: utf-8 -*-
+#
+# Copyright: Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
 
-# This file is part of Ansible
-#
-# Ansible is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Ansible is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
 ANSIBLE_METADATA = {'metadata_version': '1.0',
                     'status': ['stableinterface'],
                     'supported_by': 'community'}
@@ -96,6 +89,7 @@ except ImportError as e:
     HAS_DOPY = False
 
 from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils._text import to_native
 
 
 class JsonfyMixIn(object):
@@ -244,7 +238,8 @@ def main():
     try:
         core(module)
     except (DoError, Exception) as e:
-        module.fail_json(msg=str(e), exception=traceback.format_exc())
+        module.fail_json(msg=to_native(e), exception=traceback.format_exc())
+
 
 if __name__ == '__main__':
     main()