Add the keywords for syntactic sugar in syntac table, see issue #6.

Syntactic sugar keywords and usage models are described in
[the documentation](http://c3d.github.io/xl/#syntactic-sugar)

The added keywords added include:

      type class module function method procedure to operation
      data macro generic polymorphic iterator
      fast small global thread static
      in out inout io
      constant variable const var

They all have low priority (PREFIX 30)

src/xl.syntax

@@ -28,15 +28,18 @@ INFIX
         600     :
 
 PREFIX
-        30      data
+        30      type class module function method procedure to operation
+        30      data macro generic polymorphic iterator
+        30      fast small global thread static
+        30      in out inout io
+        30      constant variable const var
         40      loop while until
         50      property
         121     case if return yield transform
-        350     not in out constant variable const var
+        350     not
         360     ! ~
         370     - + * /
         401     FUNCTION
-        410     function procedure to type iterator
         420     ++ --
         430     &