This commit updates the natural sort for lists to give special
consideration to numbers. Previously, the invocation of
lib.strings.split did not match anything, because the intended regex was
actually escaped by lib.strings.split. Hence we use builtins.split
instead.

Also, the lib.strings.into.int only would consider the first
character of the string and turn it into a char code. This commit
implements another function to parse a string of decimal digits into
an int.

@@ -20,0 +20,4 @@
+      ## Convert from an ASCII representation of an integer to said integer.
+      ##
+      ## @type String -> Integer
+      parseInt =

@@ -33,0 +41,4 @@
+          cmpVectors =
+            a: b:
+            if a.isNumber && !b.isNumber then
+              # Numbers come even before special characters in this sorting.

@@ -33,0 +47,4 @@
+              1
+            else
+              # lib.numbers.compare happens to be compatible with both strings
+              # and integers.

@@ -39,3 +50,3 @@
           value
         ]) list;
-        isLess = a: b: (lib.lists.compare lib.numbers.compare (builtins.head a) (builtins.head b)) < 0;
+        cmpVectors =