added possibility to work via HTTP proxy

src/main/java/org/telegram/telegrambots/TelegramBotsApi.java

@@ -103,6 +103,16 @@ public class TelegramBotsApi {
         }
     }
 
+    /**
+     *
+     * @param host
+     * @param port
+     * @param scheme
+     */
+    public void setProxy(String host, int port, String scheme) {
+       TelegramApiConfiguration.getInstance().setProxy(host, port, scheme);
+    }
+
     /**
      *
      * @param botToken