smart spacing around toolbar icons

When an icon font element is empty, it contains no spacing. Otherwise,
use the space character I added in a previous commit, to automatically
add a single space between the icon and the text.

h/css/base.scss

@@ -207,6 +207,11 @@ $em: 14 / 1em !default;
     &:after {
       content: "";
     }
+    &:empty {
+      &:before {
+        content: $char;
+      }
+    }
   }
   @if $iconside == right {
     &:before {
@@ -220,5 +225,10 @@ $em: 14 / 1em !default;
       speak: none;
       font-weight: normal;
     }
+    &:empty {
+      &:after {
+        content: $char;
+      }
+    }
   }
 }
\ No newline at end of file

h/css/common.scss

@@ -423,11 +423,11 @@ blockquote {
 }
 
 .check-icon {
-  @include fonticon("\35", left, .3em);
+  @include fonticon("\35", left);
 }
 
 .x-icon {
-  @include fonticon("\36", left, .3em);
+  @include fonticon("\36", left);
 }
 
 .vis-icon {