Updating TheAdmin theme's style to let it scale down (1) and getting the features UI to behave better in smaller widths (2)

- (1) to within an 800x600. will need make use of media queries in the not too distant future
- (2) in the summary view, feature blocks would stack two-wide at the low end

--HG--
branch : dev

src/Orchard.Web/Themes/TheAdmin/Styles/site.css

@@ -52,7 +52,7 @@ body {
     font-size:62.5%; /* 10px */
 	line-height:1.6em;
     margin:0 auto 1em;
-    min-width:94.6em; /* 946px */
+    min-width:74em; /* 946px */
     padding:0;
 }
 button {