#52 Reads "" as null instead of empty string

[João Rafael]

(original: https://sourceforge.net/p/supercsv/discussion/718795/thread/fa0fc03e/)

When provided with a quoted value the reader converts any empty string to null. This should be handled differently from having no value provided at all:

Return null:

col1;col2;col3
;;

Return empty string:

col1;col2;col3
"";"";""

[Kasper B. Graversen]

We could add an argument to the string processor for configuring this behaviour

[James Bassett]

Migrated to GitHub issues: https://github.com/super-csv/super-csv/issues/13