HAMA-828: Improve code, fix typo and modify unclear comment in org.apache.hama.ml.ann package

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1549842 13f79535-47bb-0310-9956-ffa450edef68
HAMA-808: Hama Pipes Testcase

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1550154 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/hama into trunk