Fix broken property-splitting

Also, now we avoid using regex, which is apparently
more efficient, According to TIME.

vcarded.scm

@@ -50,8 +50,21 @@
 
 
 ;; Splits a key or value-element into its (potentially multiple) parameters.
+;; … basically just splits along non-escaped semi-colons.
+;;    "Bird;dad;apple\;mom" → ("Bird" "dad" "apple\;mom")
 (define (split-vcard-element key-or-value)
-  (irregex-extract "(\\\\;|[^;])*" key-or-value))
+  (let [(appendee "")]
+    (remove
+     not
+     (map (lambda (str)
+            (let [(str (string-concatenate `(,appendee ,str)))]
+              (if (and (not (string-null? str))
+                       (eq? (last (string->list str))
+                            #\\))
+                  (and (set! appendee (string-concatenate `(,str ";")))
+                       #f)
+                  (and (set! appendee "") str))))
+          (string-split key-or-value ";")))))
 
 
 ;; Parse a line of a vcard file into an alist-friendly format: