Issue #418 - Ensure TidyAttrID enum exactly matches table.

The file tidyenum.h has an attribute ID enumeration that must exactly
match the attribute_defs[] table in attrs.c.

Originally some attempt was made to keep this enum in some sort of order
but that should now be totally abandonned. Any 'new' attribute
enumerations should be added just above the last N_TIDY_ATTRIBS, and
likewise in the table, to avoid this problem.

include/tidyenum.h

@@ -553,7 +553,6 @@ typedef enum
   TidyAttr_COMPACT,           /**< COMPACT= */
   TidyAttr_CONTENT,           /**< CONTENT= */
   TidyAttr_COORDS,            /**< COORDS= */
-  TidyAttr_CROSSORIGIN,       /**< CROSSORIGIN= */
   TidyAttr_DATA,              /**< DATA= */
   TidyAttr_DATAFLD,           /**< DATAFLD= */
   TidyAttr_DATAFORMATAS,      /**< DATAFORMATAS= */
@@ -697,6 +696,7 @@ typedef enum
   TidyAttr_CONTENTEDITABLE,
   TidyAttr_CONTEXTMENU,
   TidyAttr_CONTROLS,
+  TidyAttr_CROSSORIGIN,       /**< CROSSORIGIN= */
   TidyAttr_DEFAULT,
   TidyAttr_DIRNAME,
   TidyAttr_DRAGGABLE,