HAMA-810: Refactored the Hama Pipes usage message

git-svn-id: https://svn.apache.org/repos/asf/hama/trunk@1532340 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of git://git.apache.org/hama into trunk
Updated UplinkReader to use generic types

- readNext, write & sendMessage
Added property bsp.message.class