clean up and add javadocs

Change-Id: I7f628106247de887cd91c4a4b4b55d3ebfa700c8
diff --git a/graphics/java/android/renderscript/Matrix3f.java b/graphics/java/android/renderscript/Matrix3f.java
index 2ec8c62..253506df 100644
--- a/graphics/java/android/renderscript/Matrix3f.java
+++ b/graphics/java/android/renderscript/Matrix3f.java
@@ -21,7 +21,7 @@
 
 
 /**
- * Class for exposing the rs_matrix3x3 type back to java applications.
+ * Class for exposing the native Renderscript rs_matrix3x3 type back to the Android system.
  *
  **/
 public class Matrix3f {