Small changes to accomodate Sass language advancements. Negation is now 'not' and @else exists.

frameworks/blueprint/stylesheets/blueprint/modules/_grid.sass

@@ -49,7 +49,7 @@
   +span(!n)
   @if !last
     +last
-  @if !!last
+  @else
     :margin-right = !layout_grid_margin
 
 // Mixin to a column to append n empty cols.
@@ -66,7 +66,7 @@
   :position relative
   @if !last
     :margin-left = (-!layout_grid_outer_width * !n) + !layout_grid_margin
-  @if !!last
+  @else
     :margin-left = -!layout_grid_outer_width * !n
 
 // mixin to a column to push it n columns to the right

frameworks/blueprint/stylesheets/blueprint/modules/_liquid.sass

@@ -65,7 +65,7 @@
   +span(!n)
   @if !last
     +last
-  @if !!last
+  @else
     :margin-right = !layout_liquid_margin
 
 =append(!n)