Normalize only the left margin of lists. Fix necolas#49

Prevent the addition of vertical margins on nested lists without
interferred with author expectations when customising margins
directly on 'ul' or 'ol' selectors later in the stylesheet.

Left margin needs to be normalized to remove it from IE6/7.

Close necolas#57

normalize.css

@@ -1,4 +1,4 @@
-/*! normalize.css 2011-11-04T15:36 UTC - http://github.com/necolas/normalize.css */
+/*! normalize.css 2011-11-04T15:38 UTC - http://github.com/necolas/normalize.css */
 
 /* =============================================================================
    HTML5 display definitions
@@ -239,7 +239,7 @@ sub {
 
 ul,
 ol {
-    margin: 1em 0;
+    margin-left: 0;
     padding: 0 0 0 40px;
 }