Complete 'ecsv' module

[zeitgeist]

Complete the ecsv module, with at least the following functions

1. parse_all/2 – continously scan a large binary ; either return a complete result, or an incomplete one with including the parsed lines, items and (possibly) not fully-processed part
2. parse_continue/3 – continuous incomplete parsing from parse_all/2
3. parse_single/2 – redirects to ecvs_parser:parse/2