Fixed setText() to invalidate... otherwise,

getTotalWidth(), etc. continue to use the cached
sizes.


git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@6984 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/core/com/jme3/font/Letters.java

@@ -54,6 +54,8 @@ class Letters {
             Range end = ranges.getLast();
             setColor(end.start, plainText.length(), end.color);
         }
+        
+        invalidate();
     }
 
     LetterQuad getHead() {