Merge: Kill oldstyle attributes

Remove remaining usage of old style attributes declarations `var _foo`.

Also remove the annotation `old_style_init` in the parser.

Pull-Request: #712
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --combined src/astvalidation.nit
index 578f931,a3c4bbc..b78632b
--- 1/src/astvalidation.nit
--- 2/src/astvalidation.nit
+++ b/src/astvalidation.nit
@@@ -15,6 -15,7 +15,6 @@@
  # Check the consitency of AST
  module astvalidation
  
 -private import typing
  intrude import parser
  import astbuilder
  
@@@ -51,7 -52,7 +51,7 @@@ redef class ANod
                end
                v.seen.add(self)
  
-               if _location == null then
+               if not isset _location then
                        #debug "LOCATION: unlocated node {v.path.join(", ")}"
                        _location = self.parent.location
                end