Titan-Hadoop assembly-related fixes

* Added the old data/ directory from the Faunus zipfiles back into
  titan zipfiles as the example-data/ folder (to reduce the potential
  for confusion with the db/ directory used by the Cassandra and BDB
  configs we distribute)

* Removed several duplicates of Faunus data files

* Fixed titan-hadoop meta.properties generation.  This file stores the
  titan-hadoop version and the name of the default job jar.  It's
  parsed by titan-hadoop's Tokens class.  I broke it when pulling
  titan-hadoop-core out into a separate module yesterday, but now it's
  working again (I think) for both titan-hadoop-1 and -2, though I've
  only tested -2.

* Added a mapred-site.xml to the zipfile distribution.  It sets the MR
  execution framework to "local".  The presence of this file makes it
  easy to change to YARN or classic (I changed it to yarn when
  testing).

* Tweaked the log4j-gremlin.properties in the Titan zipfile to disable
  spurious config deprecation warnings caused by HADOOP-10178
  (https://issues.apache.org/jira/browse/HADOOP-10178)
Tweak gremlin.sh log4j config for Hadoop

The root logger and org.apache.hadoop loggers now have separately
configurable loglevels.  Invoking `gremlin.sh -l <LEVEL>` sets both
loggers to the same level.  Exporting `GREMLIN_LOG_LEVEL` and
`GREMLIN_HADOOP_LOG_LEVEL` before invoking `gremlin.sh` withouth the
`-l` option allows different levels for each logger.  The defaults are
WARN for the root and INFO for Hadoop.  Setting Hadoop to INFO makes
job progress information visible.