GEOMESA-207 Remove the geomesa-dist sub-project and move the manual to geomesa.github.io

This is the first half:  Removing the geomesa-dist sub-project
from the GeoMesa build.
GEOMESA-208 getSchema(featureTypeName) should return NULL when the feature type name does not exist

Iff the feature type cannot be found by name -- here defined as whether
the attributes list can be fetched -- then the `getSchema` call should
return null.  This commit adds a pair of unit tests.
GEOMESA-207 Log configs are no longer symlinks
GEOMESA-204 Abstract geometric predicate handling and apply it to attribute queries

* Added unit tests which show attribute equals and like queries to the TestFilters.
* Changed the AIFI to use an ECQL filter rather than a polygon for topological comparisons.
* Threaded additional explainQuery 'output' calls in the IndexQueryPlanner.
GEOMESA-217 ID partitioning should hash an array of attributes rather than building a string

Hash array of attributes rather than a string built from attributes
GEOMESA-216 AvroSimpleFeature should cache converters for performance

Converters are cached in the companion object.
GEOMESA-218 fixing batch writer flush on delete of features
GEOMESA-220 Explain does not handle println well
GEOMESA-215 GeoMesa query should be exclusive of temporal filter date bounds for BEGIN, AFTER

* Partitions temporal predicates out and passes them to the STII/AIFI/IndexIterator.
* Adds special handling for DWithin.  (More special cases will be produced as we move away from FilterToAccumulo.)
Thanks to Hunter Provyn for providing the unit tests in FeatureWritersTest.scala.
GEOMESA-222 Accumulo Mini Cluster for local integration testing
GEOMESA-210 GEOMESA-61 setting default shards to the number of tservers; adding configuration for number of threads; adding index schema builder; removing mapreduce data store; adding trace logging in query planning
GEOMESA-223 Fixing delete of non-existing entries
GEOMESA-221 Create encoding for SFTs that includes index toggle

Added a utility class for working with SimpleFeatureTypes.
Toggleable secondary indexes
Upgraded specs2.
GEOMESA-209 - Identifying unique GeoHash sub-strings in a polygon is both slow and inaccurate

Added a few new unit tests, re-wrote the way we compute these
GeoHash sub-strings, and added a few utility methods to the
RectangleGeoHashIterator and the GeoHash.
Refactored based on reviewer comments; also includes some performance enhancements.
Added  to the density-iterator tests.
GEOMESA-209 - Identifying unique GeoHash sub-strings in a polygon is both slow and inaccurate

Added a few new unit tests, re-wrote the way we compute these
GeoHash sub-strings, and added a few utility methods to the
RectangleGeoHashIterator and the GeoHash.
Changes motivated by reviewer comments.