Remember script args from prev session.

This currently has an issue where you can't clear the previous args to send no args.  This is has been addressed in VSCode for May 2017 drop - microsoft/vscode#25712 (comment)

Author: rkeithhill

src/features/DebugSession.ts

@@ -110,8 +110,10 @@ export class SpecifyScriptArgsFeature implements IFeature {
 
     private command: vscode.Disposable;
     private languageClient: LanguageClient;
+    private context: vscode.ExtensionContext;
 
-    constructor() {
+    constructor(context: vscode.ExtensionContext) {
+        this.context = context;
 
         this.command =
             vscode.commands.registerCommand('PowerShell.SpecifyScriptArgs', () => {
@@ -128,13 +130,25 @@ export class SpecifyScriptArgsFeature implements IFeature {
     }
 
     private specifyScriptArguments(): Thenable<string[]> {
+        const powerShellDbgScriptArgsKey = 'powerShellDebugScriptArgs';
+
         let options: vscode.InputBoxOptions = {
             ignoreFocusOut: true,
-            placeHolder: "Enter script arguments"
+            placeHolder: "Enter script arguments or leave empty to pass no args"
+        }
+
+        let prevArgs = this.context.globalState.get(powerShellDbgScriptArgsKey, '');
+        if (prevArgs.length > 0) {
+            options.value = prevArgs;
         }
 
         return vscode.window.showInputBox(options).then(text => {
-            return text !== undefined ? new Array(text) : text;
+            if (text !== undefined) {
+                this.context.globalState.update(powerShellDbgScriptArgsKey, text);
+                return new Array(text);
+            }
+
+            return text;
         });
     }
 }

src/main.ts

@@ -115,7 +115,7 @@ export function activate(context: vscode.ExtensionContext): void {
         new RemoteFilesFeature(),
         new DebugSessionFeature(),
         new PickPSHostProcessFeature(),
-        new SpecifyScriptArgsFeature()
+        new SpecifyScriptArgsFeature(context)
     ];
 
     sessionManager =