GEOMESA-103 AvroSimpleFeature return nulls for attrs that don't exist

Making AvroSimpleFeature return nulls like SimpleFeatureImpl for attributes that don't exist in the feature
GEOMESA-95 SpatioTemporalIndexSchema should accept Query

* Refactored SpatioTemporalIndex* to be Index*.
* Changed IndexSchema to accept a GT Query.
GEOMESA-112 updating assembly for geoserver 2.5.x, accumulo 1.5.1, and hadoop 2.2
GEOMESA-113 Change naming scheme to reflect Accumulo version
GEOMESA-109 Refactor IndexSchema

* Broke up the IndexSchema file into separate files.
* Changed the STII's use of an IndexSchema to a IndexEntryDecoder.
* Pushed everything down into the IndexQueryPlanner in preparation for work on it.
GEOMESA-111 Remove the AggregatingCombiner

* In order to remove the AggregatingCombiner, we needed a new 'Is this a data row?' signal.
GEOMESA-112 adding commons-vfs2
GEOMESA-117 - Revert Data Row CQ identifier change

* Changed the DATA_CQ back to "SimpleFeatureAttribute".
* Added a new unit test to detect changes that are not backward-compatibile.
GEOMESA-116 ensuring backwards compatibility with text encoding for old tables
GEOMESA-102 filter-to-accumulo should handle ANDs and ORs

Simplistic addition that supports relativley simple
conjunction and disjunction.  Does NOT support negation.

Reviewed by @anthonyccri
Merge branch 'master' into wip_index_only_iterator2

Conflicts:
	geomesa-core/src/main/scala/geomesa/core/index/SpatioTemporalIndexSchema.scala
	geomesa-core/src/main/scala/geomesa/core/iterators/SpatioTemporalIntersectingIterator.scala
Add in trigger logic for IndexIterator.
Some cleanup to revert trivial changes relative to master.
Refactored the IndexIteratorTest to use getFeatures.
More changes to trigger logic and the encoding of the index values to a SimpleFeature.

The logic still needs more work to elegantly understand the target schema.
GEOMESA-106 Add TubeSelect WPS process to GeoMesa
GEOMESA-80,GEOMESA-81,GEOMESA-123,GEOMESA-124

* Fixing ingest for feature sources with LineString geometries
* Fixing test logging by removing conflicting log4j jars
* Removing all source references to log4j
* Setting mapreduce.task.classpath.user.precedence to true to allow a geomesa-distributed-runtime to override the version of hsqldb provided by the hadoop cluster
Code improvements, bug fixes and cleanup. The IndexIterator now passes its tests.
Refactoring to use findTop() from the STII, and instead override seekData in the II.
Reformatted some code.