Add proper shebangs and block comments

settings.py.default

@@ -1,3 +1,10 @@
+#!/usr/bin/env python3
+"""
+settings.py
+
+User-defined settings used by imgupload.py.
+"""
+
 UPLOAD_FOLDER = "/path/to/images"
 ALLOWED_EXTENSIONS = [".png", ".jpg", ".jpeg", ".svg", ".bmp", ".gif", ".ico",  ".webp"]
 ROOTURL = "https://example.com/"