warning-fix: remove 'unnecessary parentheses'-warning

GCC 8.2 warns:
  csv.h:1099:22: warning: unnecessary parentheses in declaration of ‘row’ [-Wparentheses]

This commit fixes it.

Author: pboettch

csv.h

@@ -1112,7 +1112,7 @@ namespace io{
         private:
                 LineReader in;
 
-                char*(row[column_count]);
+                char*row[column_count];
                 std::string column_names[column_count];
 
                 std::vector<int>col_order;