added missing @since comments

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@619928 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/math/stat/descriptive/moment/VectorialCovariance.java

@@ -25,6 +25,7 @@ import org.apache.commons.math.linear.RealMatrixImpl;
 
 /**
  * Returns the covariance matrix of the available vectors.
+ * @since 1.2
  * @version $Revision$ $Date$
  */
 public class VectorialCovariance implements Serializable {

src/java/org/apache/commons/math/stat/descriptive/moment/VectorialMean.java

@@ -22,6 +22,7 @@ import org.apache.commons.math.DimensionMismatchException;
 
 /**
  * Returns the arithmetic mean of the available vectors.
+ * @since 1.2
  * @version $Revision$ $Date$
  */
 public class VectorialMean implements Serializable {