Merge pull request #410 from robruma/range_documentation_update

Adding markdown for the range() function's 3rd argument

Author: Morgan Haskel

README.markdown

@@ -382,6 +382,8 @@ Calling the class or definition from outside the current module will fail. For e
 
   Non-integer strings are accepted; `range("a", "c")` returns ["a","b","c"], and `range("host01", "host10")` returns ["host01", "host02", ..., "host09", "host10"].
 
+  Passing a third argument will cause the generated range to step by that interval, e.g. `range("0", "9", "2")` returns ["0","2","4","6","8"]
+
   *Type*: rvalue
 
 * `reject`: This function searches through an array and rejects all elements that match the provided regular expression. For example, `reject(['aaa','bbb','ccc','aaaddd'], 'aaa')` returns ['bbb','ccc']. *Type*: rvalue