Add missing xssf method

git-svn-id: https://svn.apache.org/repos/asf/poi/branches/ooxml@685096 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFName.java

@@ -35,6 +35,10 @@ public class XSSFName implements Name {
 		this.ctName = name;
 	}
 	
+	public boolean isFunctionName() {
+		// TODO Figure out how HSSF does this, and do the same!
+		return false;
+	}
 	/**
 	 * Returns the underlying named range object
 	 */