maint: change the host of ``start_server()`` listen default to 0.0.0.0

pywebio/platform/django.py

@@ -101,7 +101,7 @@ def webio_view(applications, cdn=True,
 urlpatterns = []
 
 
-def start_server(applications, port=8080, host='localhost', cdn=True, static_dir=None,
+def start_server(applications, port=8080, host='', cdn=True, static_dir=None,
                  allowed_origins=None, check_origin=None,
                  session_expire_seconds=None,
                  session_cleanup_interval=None,

pywebio/platform/flask.py

@@ -100,7 +100,7 @@ def webio_view(applications, cdn=True,
     return view_func
 
 
-def start_server(applications, port=8080, host='localhost', cdn=True, static_dir=None,
+def start_server(applications, port=8080, host='', cdn=True, static_dir=None,
                  allowed_origins=None, check_origin=None,
                  session_expire_seconds=None,
                  session_cleanup_interval=None,

pywebio/platform/tornado_http.py

@@ -108,7 +108,7 @@ def webio_handler(applications, cdn=True,
     return MainHandler
 
 
-def start_server(applications, port=8080, host='localhost',
+def start_server(applications, port=8080, host='',
                  debug=False, cdn=True, static_dir=None,
                  allowed_origins=None, check_origin=None,
                  auto_open_webbrowser=False,