Fixed navbar floats

Also minor formatting tweaks

Author: kane-c

stylus/navbar.styl

@@ -321,12 +321,12 @@
 //
 // Declared after the navbar components to ensure more specificity on the margins.
 
-@media (min-width: $grid-float-breakpoint)
+@media (min-width $grid-float-breakpoint)
   .navbar-left
-    pull-left()
+    @extends .pull-left
 
   .navbar-right
-    pull-right();
+    @extends .pull-right
     margin-right -($navbar-padding-horizontal)
 
     ~ .navbar-right