Fix case on style import

Author: brpaz

browser/styles/main/index.styl

@@ -4,7 +4,7 @@
 global-reset()
 @import '../shared/*'
 @import './ArticleNavigator'
-@import './ArticleTopbar'
+@import './ArticleTopBar'
 @import './ArticleList'
 @import './ArticleDetail'
 @import './modal/*'