[css-backgrounds-3] Make keyword mapping more precise for border-image-repeat. Fixes #148.

Author: fantasai

css-backgrounds/Overview.html

@@ -2381,8 +2381,12 @@ <h3 class="heading settled" data-level="6.5" id="the-border-image-repeat"><span
       <td>no 
    </table>
    <p>This property specifies how the images for the sides and the middle
-part of the border image are scaled and tiled. The first keyword applies
-to the horizontal sides, the second to the vertical ones; see <a href="#border-image-process">Drawing the Border Image</a>.
+part of the border image are scaled and tiled.
+The first keyword applies to the horizontal scaling and tiling
+of the top, middle and bottom parts,
+the second to the vertical scaling and tiling
+of the left, middle and right parts;
+see <a href="#border-image-process">Drawing the Border Image</a>.
 If the second keyword is absent, it is assumed to be the same as the first.
 Values have the following meanings: </p>
    <dl>

css-backgrounds/Overview.src.html

@@ -2534,9 +2534,12 @@ <h3 id="the-border-image-repeat">Image Tiling: the 'border-image-repeat' propert
 </table>
 
 <p>This property specifies how the images for the sides and the middle
-part of the border image are scaled and tiled. The first keyword applies
-to the horizontal sides, the second to the vertical ones; see
-<a href="#border-image-process">Drawing the Border Image</a>.
+part of the border image are scaled and tiled.
+The first keyword applies to the horizontal scaling and tiling
+of the top, middle and bottom parts,
+the second to the vertical scaling and tiling
+of the left, middle and right parts;
+see <a href="#border-image-process">Drawing the Border Image</a>.
 If the second keyword is absent, it is assumed to be the same as the first.
 Values have the following meanings: