Fixed a problem with processing CSV lines containing empty fields.

Example:
- Before the fix:
  > (CSV:parse-string "1,2,3,,4,,5,,")
  (("1" "2" "3"))
- After the fix:
  > (CSV:parse-string "1,2,3,,4,,5,,")
  (("1" "2" "3" "" "4" "" "5" ""))

Discussion at the newLISP Fan Club about this issue is at
http://newlispfanclub.alh.net/forum/viewtopic.php?f=16&t=4334
Merge pull request #1 from cryptorick/empty-field-fix

Fixed a problem with processing CSV lines containing empty fields.