Update vscode tasks and launch info

.vscode/launch.json

@@ -7,10 +7,10 @@
         {
             "type": "gdb",
             "request": "launch",
-            "name": "Launch Program (gdb)",
-            "target": "./lmdb-d",
-            "cwd": "${workspaceRoot}",
-            "preLaunchTask": "build-host",
+            "name": "Launch Demo Program (gdb)",
+            "target": "./lmdb-d-demo",
+            "cwd": "${workspaceRoot}/docs/lmdb-d-demo/",
+            "preLaunchTask": "build-demo",
             "arguments": "-v"
         },
         {
@@ -18,8 +18,8 @@
             "type": "lldb-mi",
             "request": "launch",
             "target": "./lmdb-d",
-            "preLaunchTask": "build-host",
-            "cwd": "${workspaceRoot}",
+            "preLaunchTask": "build-demo",
+            "cwd": "${workspaceRoot}/docs/lmdb-d-demo/",
             "arguments": "-v"
         }
     ]

.vscode/tasks.json

@@ -16,6 +16,19 @@
                 "$gcc"
             ]
         },
+        {
+            // Requires dub and ldc to be installed on host
+            "label": "build-demo",
+            "type": "shell",
+            "command": "cd docs/lmdb-d-demo && dub build --compiler=ldc2 -v",
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            },
+            "problemMatcher": [
+                "$gcc"
+            ]
+        },
         {
             // Requires dub and ldc to be installed on host
             "label": "test-host",