TSV values can contain newlines and tabs which should be escaped

[svetlyak40wt]

Without escaping, the library can produce broken serialized lines or broken values during parsing.

Right now it is not supported:

POFTHEDAY> (concatenate 'string
                        "Hello"
                        '(#\Newline #\Tab)
                        "World!")
"Hello
	World!"

;; This call should produce a single line,
;; replacing a newline with \n and tab with \t:
POFTHEDAY> (cl-ltsv:alist-ltsv (list (cons "message" *)))
"message:Hello
	World!"

;; Parsing does not process escaped symbols either:

POFTHEDAY> (cl-ltsv:parse-line "message:Hello\\n\\tWorld!")
(("message" . "Hello\\n\\tWorld!"))

More info on escaping rules is available in this TSV article.