Give warning when "NaN"s found

Author: chrisgorgo

validators/tsv.js

@@ -68,7 +68,7 @@ var TSV = function TSV (file, contents, fileList, callback) {
                     character: "at column # " + (j+1),
                     code: 23
                 }));
-            } else if ((value === "NA" || value === "na" || value === "nan") && !NACells) {
+            } else if ((value === "NA" || value === "na" || value === "nan" || value === "NaN") && !NACells) {
                 NACells = true;
                 // check if missing value is properly labeled as 'n/a'
                 issues.push(new Issue({