Issue #102 - Update FieldCount

#102 DetectColumnCountChanges and CsvBadDataException issue when there are extra columns in some rows

- Modified how the FieldCount is set
  1. If header does not exist, then update FieldCount (same as before)
  2. If header does exist and it is the first row, then update FieldCount
- Added a unit test InconsistentColumnsMultipleRowsTest()