HAMA-878: PartitioningRunner.Sorter doesn't allows duplicate key

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1572838 13f79535-47bb-0310-9956-ffa450edef68
HAMA-878: PartitioningRunner.Sorter doesn't allows duplicate key

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1572839 13f79535-47bb-0310-9956-ffa450edef68
HAMA-879: Errors for messages with wrong destination should be more clear (Anastasis Andronidis via edwardyoon)

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1573268 13f79535-47bb-0310-9956-ffa450edef68
HAMA-880: Check whether input records are in order by vertex ID (edwardyoon)

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1573269 13f79535-47bb-0310-9956-ffa450edef68
Fix toString() method.

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1573446 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare release 0.6.4-RC1

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1573511 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1573513 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/hama into trunk