more configuration;

--- a/src/Tools/VSCode/extension/package.json	Sun Jan 01 13:15:50 2017 +0100
+++ b/src/Tools/VSCode/extension/package.json	Sun Jan 01 13:38:20 2017 +0100
@@ -36,6 +36,12 @@
                     "type": "string",
                     "default": "",
                     "description": "ISABELLE_HOME directory"
+                },
+                "isabelle.arguments": {
+                    "type": "array",
+                    "items": { "type": "string" },
+                    "default": [],
+                    "description": "command-line arguments for isabelle vscode_server"
                 }
             }
         }

--- a/src/Tools/VSCode/extension/src/extension.ts	Sun Jan 01 13:15:50 2017 +0100
+++ b/src/Tools/VSCode/extension/src/extension.ts	Sun Jan 01 13:38:20 2017 +0100
@@ -9,11 +9,13 @@
 
 export function activate(context: vscode.ExtensionContext)
 {
-  let isabelle_home = vscode.workspace.getConfiguration("isabelle").get("home");
+  let isabelle_home = vscode.workspace.getConfiguration("isabelle").get<string>("home");
+  let isabelle_arguments =
+    vscode.workspace.getConfiguration("isabelle").get<Array<string>>("arguments");
 
   let run = {
     command: path.join(isabelle_home, "bin", "isabelle"),
-    args: ["vscode_server"]
+    args: ["vscode_server"].concat(isabelle_arguments)
   };
   let server_options: ServerOptions =
   {