If a text file is uncompressed, scanner is able to read from direct buffer
Other cases, it read from input stream.
This patch includes some refactoring as follows:
- rename properties
- csvfile.delimiter to text.delimiter
- csvfile.null to text.null
- Add DelimitedLineReader
- it will be easier to implement text-format variations.
- Use the java Unsafe for split line and field
- It will be better performance
- Remove seekable interface
- We use the CSVFile to just debugging