Remove ignore.txt entries (#29)

* Remove some ignore.txt entries.

* Prepare for validate-plugins.

plugins/connection/docker.py

@@ -13,7 +13,7 @@ DOCUMENTATION = '''
     author:
         - Lorin Hochestein (!UNKNOWN)
         - Leendert Brouwer (!UNKNOWN)
-    connection: docker
+    name: docker
     short_description: Run tasks in docker containers
     description:
         - Run commands or put/fetch files to an existing docker container.

plugins/inventory/docker_machine.py

@@ -7,7 +7,6 @@ __metaclass__ = type
 
 DOCUMENTATION = '''
     name: docker_machine
-    plugin_type: inventory
     author: Ximon Eighteen (@ximon18)
     short_description: Docker Machine inventory source
     requirements:

plugins/inventory/docker_swarm.py

@@ -9,7 +9,6 @@ __metaclass__ = type
 
 DOCUMENTATION = '''
     name: docker_swarm
-    plugin_type: inventory
     author:
       - Stefan Heitmüller (@morph027) <stefan.heitmueller@gmx.com>
     short_description: Ansible dynamic inventory plugin for Docker swarm nodes.

plugins/modules/docker_stack.py

@@ -36,7 +36,7 @@ options:
         referring to the path of the compose file on the target host
         or the YAML contents of a compose file nested as dictionary.
     type: list
-    # elements: raw
+    elements: raw
     default: []
   prune:
     description: