Merge branch 'master' into my_master
moved the codec to codec package
Minor.
Relocate codec classes to codec package.

Conflicts:
	apps/src/main/java/com/datatorrent/apps/logstream/DimensionOperator.java
	apps/src/main/java/com/datatorrent/apps/logstream/LogstreamTopN.java
Merge pull request #819 from 243826/my_master

Relocated codec classes to lib.codec package.