Added new custom header structure

+ Moved custom header rewrite to dpcore
+ Restructure dpcore header rewrite sequence
+ Added advance custom header settings (zoraxy to upstream and zoraxy to downstream mode)
+ Added header remove feature
+ Removed password requirement for SMTP #80
+ Completed stream proxy module (TCP and UDP)
+ Optimized UX for reminding user to click Apply after port change
+ Added version number to footer #160

src/web/main.css

@@ -509,6 +509,16 @@ body{
     }
   }
 
+  /* Remind message for user forgetting to click Apply button*/
+  #applyButtonReminder{
+    position: absolute; 
+    bottom:-1.6em; 
+    left: 0; 
+    font-weight: bolder; 
+    color: #faac26; 
+    display:none;
+  }
+
 /*
   HTTP Proxy & Virtual Directory
 */