Update snapshot examples for version 0.12.1-SNAPSHOT
CDK-200: Fix http port conflict with yarn.

Now the demo and logging-webapp examples use 8034 instead of 8080.
Add license header.
CDK-252: Configure log4j in examples.

This uses INFO for the root and DEBUG for all dataset implementations
and the example code. Class names are supressed to simplify the output
to just log messages.
Update staging example to use hive-compatible names.
Update stable examples for version 0.12.1