Updated HTTP request API (markdown)

HTTP-request-API.md

@@ -99,6 +99,7 @@ Parameter | Value Range | Description | Since Version
 &NM= | 0 or 1 | Cronixie Time or Countdown mode | 0.4
 &NB= | 0 or 1 | Cronixie Backlight | 0.4
 &IT | none | Include UI color theme in API response | 0.8.2
+&RD= | 0 or 1 | Toggle realtime UDP | 0.8.4
 
 ## XML response
 This is the XML file sent as response to every API call.