Add a variable for the root directory.

This way, it can be easily overridden in other .less files.

less/font-awesome.less

@@ -22,13 +22,15 @@
 
     */
 
+@fontAwesomePath: '../font';
+
 @font-face {
   font-family: 'FontAwesome';
-  src: url('../font/fontawesome-webfont.eot');
-  src: url('../font/fontawesome-webfont.eot?#iefix') format('embedded-opentype'),
-    url('../font/fontawesome-webfont.woff') format('woff'),
-    url('../font/fontawesome-webfont.ttf') format('truetype'),
-    url('../font/fontawesome-webfont.svg#FontAwesome') format('svg');
+  src: url('@{fontAwesomePath}/fontawesome-webfont.eot');
+  src: url('@{fontAwesomePath}/fontawesome-webfont.eot?#iefix') format('embedded-opentype'),
+    url('@{fontAwesomePath}/fontawesome-webfont.woff') format('woff'),
+    url('@{fontAwesomePath}/fontawesome-webfont.ttf') format('truetype'),
+    url('@{fontAwesomePath}/fontawesome-webfont.svg#FontAwesome') format('svg');
   font-weight: normal;
   font-style: normal;
 }