Feature/8333 connector cleanup

1. SparkConnector has been simplified such that in no longer attempts to pass jars to spark based on the SPARK_CLASSPATH variable, classloader, or from Maven.  Additionally, the SparkConnector no longer looks for non-standard args to specify the master and spark home parameters, instead relying on standard  mechanisms provided by the spark-submit script.
2. The tile-generation project now produces an assembly jar that contains the classes from the dependent libraries it needs to run that are not provided by the CDH install.  The assembly jar is packed into the zip distribution created in tile-packaging, along with source and doc jars.