Adjusted code for DATA LIST (free/list) to be more consistent with SPSS in

Adjusted code for DATA LIST (free/list) to be more consistent with SPSS in
the instance where delimiters are explicitly set.  In particular, if a delim.
is explicitly set, we treat quotes / apostrophes as normal chars:

From SPSS Syntax Base manual:
For data with explicitly specified value delimiters (for example, DATA LIST FREE (","):
· Multiple delimiters without any intervening space can be used to specify missing data.
· The specified delimiters cannot occur within a data value, even if you enclose the value
in quotation marks or apostrophes.