GEOMESA-232 Fixing CoverageReader, also upgrades to geotools 11.2 and scala 2.10.4
GEOMESA-199 Update our POM to support releases to LocationTech's Nexus instance
GEOMESA-237 Convert AvroSimpleFeature to WKB

* Use WKB (Well Known Binary) instead of WKT (Well Known Text) for AvroSimpleFeature
* Results in 20x speedup on serialization/deserialization
Merge branch 'master' into fcr_spark
Merge and update readme