API: Support for the conversation api call from GNU Social

doc/api.md

@@ -388,6 +388,18 @@ Friendica doesn't allow showing friends of other users.
 ---
 ### statusnet/config (*)
 
+---
+### statusnet/conversation (*; AUTH)
+It shows all direct answers (excluding the original post) to a given id.
+
+#### Parameter
+* id: id of the post
+* count: Items per page (default: 20)
+* page: page number
+* since_id: minimal id
+* max_id: maximum id
+* include_entities: "true" shows entities for pictures and links (Default: false)
+
 ---
 ### statusnet/version (*)
 

include/api.php

@@ -1550,6 +1550,7 @@
 		return api_apply_template("timeline", $type, $data);
 	}
 	api_register_func('api/conversation/show','api_conversation_show', true);
+	api_register_func('api/statusnet/conversation','api_conversation_show', true);
 
 
 	/**