Merging logstream branch into Malhar master

The logstream application can be found under apps directory. It contains both old and the new versions. The old
version has operators added to the dag for each type and filter. The new version is optimized to have a single
line of logical dag and then partitions itself based on log types and filters applied on each type. It also
sends meta information to the each aggregation such as type, filter, dimension etc to identify the aggregation.

For old version, please see apps/src/main/java/com/datatorrent/apps/logstream/Application.java
For new version, please see apps/src/main/java/com/datatorrent/apps/logstream/Application1.java