Updates Occurrence and VerbatimOccurrence classes following review in http://dev.gbif.org/issues/browse/POR-1667 Changes include renaming identificationDate to dateIdentified, fixing misspelling of accurracy to accuracy, adding @Min and @Max annotations to year, month, and day properties, and adding some javadoc to depth, depthAccuracy, altitude, altitudeAccuracy, and publishingCountry getters.