Add cp command and copy api endpoint

The cp command and copy api endpoint allows users
to copy files and or folders from a containers filesystem.

Closes #382

docs/sources/api/docker_remote_api_v1.3.rst

@@ -525,6 +525,38 @@ Remove a container
         :statuscode 500: server error
 
 
+Copy files or folders from a container
+**************************************
+
+.. http:post:: /containers/(id)/copy
+
+	Copy files or folders of container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/4fa6e0f0c678/copy HTTP/1.1
+	   Content-Type: application/json
+
+	   {
+		"Resource":"test.txt"
+	   }
+
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/octet-stream
+	   
+	   {{ STREAM }}
+
+	:statuscode 200: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
 2.2 Images
 ----------
 
@@ -1091,7 +1123,6 @@ Monitor Docker's events
         :statuscode 200: no error
         :statuscode 500: server error
 
-
 3. Going further
 ================