Add documentation

[jferard]

Imported from CSVSniffer. Created at: "2016-12-19T22:02:27Z"

The README.md is a but short : there should be some examples. E.g. how to parse a file, given the expected fields and a encoding set to UTF-8 or ISO.

1. Create a InputStreamUTF8OrByteCharsetReader from the stream
2. Buffer the reader and mark at start position
3. Analyze the first line, deduce the CSVFormat
4. reset to reader start and parse the file.