filer: recursive deletion optionally ignoring any errors

Filer-Server-API.md

@@ -71,5 +71,9 @@ curl  "http://localhost:8888/javascript/?pretty=y&lastFileName=new_name.js&limit
 ## Delete a folder
 
 ```bash
+// recursively delete all files and folders under a path
 > curl -X DELETE http://localhost:8888/path/to/dir?recursive=true
+// recursively delete everything, ignoring any recursive error
+> curl -X DELETE http://localhost:8888/path/to/dir?recursive=true&ignoreRecursiveError=true
+
 ```