Minor fix

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1526783 13f79535-47bb-0310-9956-ffa450edef68
Add trace code for debug.

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1526815 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/hama into trunk
modify NeuralNetwork and NeuralNetworkTest