GEOMESA-155 fix for non-thread-safe map 1.4

this is the accumulo1.4 branch fix for geomesa-155, Changed attributeNameLookUp into a HashMap with SynchronizedMap traits. It should fix thread safety issues...
that should handle it :+1:  for everyone else interested: http://www.scala-lang.org/docu/files/collections-api/collections_11.html