Backport fixes for DarkBetter theme icons (#2822)

Author: jevenski

plugins/theme/themes/Dark/stable.css

@@ -20,4 +20,3 @@
 .stable-active-header {border-color: threedface !important}
 .stable-separator-header {background: #181818;}
 .stable-scrollpos { background: #181818; color: #333333; }
-

plugins/theme/themes/DarkBetter/stable.css

@@ -19,4 +19,4 @@
 
 .stable-active-header {border-color: threedface !important}
 .stable-separator-header {background: #181818}
-.stable-scrollpos {background: #181818; color: #333333}
+.stable-scrollpos {background: #181818; color: #333333}

plugins/theme/themes/DarkBetter/style.css

@@ -149,12 +149,10 @@ div#preload {
     background-image: url(./images/tb_moved.svg);
     background-image: url(./images/tb_search.svg);
     background-image: url(./images/tb_rss.svg);
-    background-image: url(./images/rb_rss_group.svg);
+    background-image: url(./images/tb_rss_group.svg);
     background-image: url(./images/tb_setting.svg);
     background-image: url(./images/menuexp.svg);
     background-image: url(./images/menusel.svg);
-    background-image: url(./images/tb_rss.svg);
-    background-image: url(./images/t_error.svg);
     background-image: url(./images/close.svg);
     background-image: url(./images/yellow.svg);
     background-image: url(./images/red.svg);
@@ -163,27 +161,21 @@ div#preload {
     background-image: url(./images/pnl_close.svg);
     background-image: url(./images/file.svg);
     background-image: url(./images/dir.svg);
-    background-image: url(./images/dir.svg);
     background-image: url(./images/t_down.svg);
     background-image: url(./images/t_up.svg);
     background-image: url(./images/t_inactive.svg);
     background-image: url(./images/t_paused.svg);
+    background-image: url(./images/t_error.svg);
     background-image: url(./images/t_error_down.svg);
     background-image: url(./images/t_error_up.svg);
-    background-image: url(./images/t_error.svg);
     background-image: url(./images/t_completed.svg);
     background-image: url(./images/t_queued_down.svg);
     background-image: url(./images/t_queued_up.svg);
     background-image: url(./images/t_active.svg);
     background-image: url(./images/t_all.svg);
-    background-image: url(./images/rb_rss.svg);
-    background-image: url(./images/pnl_open.svg);
     background-image: url(./images/quest.svg);
     background-image: url(./images/go.svg);
     background-image: url(./images/plugin.svg);
-    background-image: url(./images/yellow.svg);
-    background-image: url(./images/red.svg);
-    background-image: url(./images/green.svg);
 }
 div#cover {background: #181818}
 div#msg {background: #181818; border-top: 1px solid #333333; border-bottom: 1px solid #333333}