#628 UTF-16/32 support for CSV files

[High Performance Coder]

These can be detected via the "byte order mark". Need to process the input buffer through utftoutf prior to processing the data in UTF-8.

For now, the workaround is to use a spreadsheet to convert the UTF-16/32 file into UTF-8 by first saving as a spreadsheet (eg .ods or .xlxs), then saving as a CSV (the option for UTF-8 encoding should come up then).