Introduce lib.functions which includes helper functions

Splitting macros and functions into different packages and source code
makes it easier to look at.   Functions currently implemented:
- range: like Python's range
- parse-integer*: parse-integer but junk-allowed is set to t.

packages.lisp

@@ -24,6 +24,12 @@
    :while
    :-> :fn))
 
+(defpackage lib.functions
+  (:use :cl :lib.macros)
+  (:export
+   :range
+   :parse-integer*))
+
 (defpackage main
   (:use :cl :lib.macros)
   (:export :start))