Update vr180-player.js and index.html to use HTML text for enterVrBtn and fix exit VR label

index.html

@@ -11,9 +11,9 @@
 			<video id="vrVideo" controls crossOrigin="anonymous" playsinline webkit-playsinline>
 				<source src="REPLACE_THIS.mp4" type="video/mp4">
 			</video>
-			<button id="enterVrBtn">Enter VR</button>
 			</div>
 		</div>
+		<button id="enterVrBtn" data-enter-vr-text="Enter VR">Enter VR</button>
 	<script type="module" src="vr180-player.js"></script>
 </body>
-</html>
+</html>