Implement general Range iterator using .pred and .succ

Spec says the Range iterator should just the .succ method to get the next
element. So that is what we do if we have no specialized iterator.

src/core/Range.pm

@@ -165,9 +165,26 @@ my class Range is Cool does Iterable does Positional {
             }.new($value)
         }
 
-        # XXX do other cases here
+        # General case according to spec
         else {
-            nqp::die('Range iterator NYI')
+            class :: does Iterator {
+                has $!i;
+                has $!e;
+
+                method new($i is copy, $e is copy) {
+                    my \iter = self.CREATE;
+                    nqp::bindattr(iter, self, '$!i', $i);
+                    nqp::bindattr(iter, self, '$!e', $e);
+                    iter
+                }
+
+                method pull-one() {
+                    $!i.=succ;
+                    $!i <= $!e ?? $!i !! IterationEnd
+                }
+
+                method is-lazy() { True }
+            }.new($value, $!excludes-max ?? $!max.pred !! $!max)
         }
     }
     multi method list(Range:D:) { List.from-iterator(self.iterator) }