fix(layout): Incorrect default width for main content

When using a collapsed layout it seems col-sm-8 was being used instead
of col-sm12. This does not matter for standard width pages but has an
effect on full-width pages in  narrow layout scenarios - the page does
not become full width. This happens because col-sm-* are defined after
the col-md-* classes and they override.

Bug introduced in 2cadd17

src/index.html

@@ -93,7 +93,7 @@
 
         <!-- each view must specify the controller they use -->
         <div id="content-wrapper"
-             class="col-sm-8"
+             class="col-sm-12"
              ng-class="{ 'col-md-12': fullWidth, 'col-md-8': !fullWidth, 'col-md-pull-2': !fullWidth }"
              ng-view autoscroll>
         </div>