Rename Angular2Spa to AngularSpa, plus rephrase "Angular 2" as "Angular" in many places

templates/AngularSpa/ClientApp/app/components/counter/counter.component.ts

@@ -0,0 +1,13 @@
+import { Component } from '@angular/core';
+
+@Component({
+    selector: 'counter',
+    templateUrl: './counter.component.html'
+})
+export class CounterComponent {
+    public currentCount = 0;
+
+    public incrementCounter() {
+        this.currentCount++;
+    }
+}