Cleanup: Resolve HKEY conflict

Both the MS headers and blender headers define the HKEY
which gives all kind of inclusion order issues.

This diff renames all *KEY constants to EVT_*KEY to resolve
this conflict.

Reviewed By: brecht , dfelinto

Differential Revision: http://developer.blender.org/D7164

source/blender/editors/space_graph/graph_edit.c

@@ -1576,8 +1576,8 @@ static int graphkeys_decimate_modal(bContext *C, wmOperator *op, const wmEvent *
 
   switch (event->type) {
     case LEFTMOUSE: /* confirm */
-    case RETKEY:
-    case PADENTER: {
+    case EVT_RETKEY:
+    case EVT_PADENTER: {
       if (event->val == KM_PRESS) {
         decimate_exit(C, op);
 
@@ -1586,7 +1586,7 @@ static int graphkeys_decimate_modal(bContext *C, wmOperator *op, const wmEvent *
       break;
     }
 
-    case ESCKEY: /* cancel */
+    case EVT_ESCKEY: /* cancel */
     case RIGHTMOUSE: {
       if (event->val == KM_PRESS) {
         decimate_reset_bezts(dgo);