Add VS Code support

Adds basic configuration for VS Code for QEMU and STM32F3DISCOVERY.

.vscode/tasks.json

@@ -0,0 +1,24 @@
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558 
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            /*
+             * This is the default cargo build task,
+             * but we need to provide a label for it,
+             * so we can invoke it from the debug launcher.
+             */
+            "label": "build",
+            "type": "cargo",
+            "subcommand": "build",
+            "problemMatcher": [
+                "$rustc"
+            ],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        },
+    ]
+}