Fixes to for loops. Added elseif and else

samples/range.chai

@@ -11,5 +11,5 @@ def for_each(container, function)
 
 var vec = [1,2,3,4,5,6,7,8,9, "hi", 4.5]
 
-for_each(vec, function(x) { print(x); } );
+for_each(vec, fun(x) { print(x); } );