fs.readFileSync(filename, 'utf8') doesn't strip BOM markers (#580)

Taking the workaround specified here nodejs/node-v0.x-archive#1918

Author: rajkumar42

src/assets.ts

@@ -243,7 +243,7 @@ function addTasksJsonIfNecessary(info: protocol.DotNetWorkspaceInformation, path
 
 function hasWebServerDependency(projectJsonPath: string) {
     let projectJson = fs.readFileSync(projectJsonPath, 'utf8');
-    let projectJsonObject = JSON.parse(projectJson);
+    let projectJsonObject = JSON.parse(projectJson.replace(/^\uFEFF/, ''));
 
     if (projectJsonObject == null) {
         return false;