CSVRecord.get(String) throws IAE if the column is not mapped (does not exist). This is similar to what JDBC does in ResultSet. Add getBoolean(String) API and tests.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1509431 13f79535-47bb-0310-9956-ffa450edef68