Enhancement processing fails after git pull

[ewpatton]

During a git pull I went from a6ff0fe to 6225d4c and running any enhancement results in a stack trace being thrown and no turtle. After tracing back through the commits it appears that this problem was introduced in commit bf2a5c9 since commits prior to that one successfully generate turtle and load it into Virtuoso.

Stack trace:

Exception in thread "main" java.lang.NullPointerException
    at edu.rpi.tw.data.csv.valuehandlers.ResourceValueHandler.handleValue(ResourceValueHandler.java:348)
    at edu.rpi.tw.data.csv.CSVtoRDF.handleValue(CSVtoRDF.java:3331)
    at edu.rpi.tw.data.csv.CSVtoRDF.visit(CSVtoRDF.java:2953)
    at edu.rpi.tw.data.csv.CSVParser.visitRecords(CSVParser.java:298)
    at edu.rpi.tw.data.csv.CSVtoRDF.toRDF(CSVtoRDF.java:1327)
    at edu.rpi.tw.data.csv.CSVtoRDF.main(CSVtoRDF.java:476)