[Compass Core] New content char is the best practice for the pie-clearfix now. Avoids the gap at the bottom in some browsers.

Closes GH-179

frameworks/compass/stylesheets/compass/utilities/general/_clearfix.scss

@@ -18,12 +18,9 @@
 // [Easy Clearing](http://www.positioniseverything.net/easyclearing.html)
 // has the advantage of allowing positioned elements to hang
 // outside the bounds of the container at the expense of more tricky CSS.
-//
-// This method of clearing might cause a gap at the bottom of the page in
-// some browsers when used on the last element of the page.
 @mixin pie-clearfix {
   &:after {
-    content    : " ";
+    content    : "\0020";
     display    : block;
     height     : 0;
     clear      : both;

test/fixtures/stylesheets/compass/css/utilities.css

@@ -7,7 +7,7 @@
 .pie-clearfix {
   display: inline-block; }
   .pie-clearfix:after {
-    content: " ";
+    content: "\0020";
     display: block;
     height: 0;
     clear: both;