rename new fragment style

README.md

@@ -768,7 +768,7 @@ The default fragment style is to start out invisible and fade in. This style can
 	<p class="fragment fade-out">fade-out</p>
 	<p class="fragment fade-up">fade-up (also down, left and right!)</p>
 	<p class="fragment fade-in-then-out">fades in, then out when we move to the next step</p>
-	<p class="fragment fade-in-then-half-out">fades in, then 50% out when we move to the next step</p>
+	<p class="fragment fade-in-then-semi-out">fades in, then obfuscate when we move to the next step</p>
 	<p class="fragment highlight-current-blue">blue only once</p>
 	<p class="fragment highlight-red">highlight-red</p>
 	<p class="fragment highlight-green">highlight-green</p>