GEOMESA-373,GEOMSA-374,GEOMESA-375,GEOMESA-376

* fixing plugin to remove unnecessary dependencies
* moving all logging to log4j & slf4j via scalalogging since mini accumulo (used in tests) must use log4j and not logback
* shading guava and apache commons projects into geomesa-plugin uber jar so that existing geoserver jars don't need to be removed
* upgrading geoserver to 2.5.2 to match geotools 11.2
GEOMESA-363 Remove HADOOP_CLIENT from geomesa-tools shell wrapper

This JAR isn't required to be on the GeoMesa-Tools classpath, so it has been removed to not cause further errors.