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.

odraw.asd

@@ -2,6 +2,7 @@
   :depends-on (:deploy)
   :components ((:file "packages")
                (:file "lib.macros")
+               (:file "lib.functions")
                (:file "main"))
   :build-operation "deploy-op"
   :build-pathname "odraw"