updated liteserver

- new methods for liteserver/liteclient
- added ADNL/DHT client-only work mode
- fixed crash in ADNL

tdutils/td/utils/port/detail/Epoll.cpp

@@ -14,7 +14,7 @@
     You should have received a copy of the GNU Lesser General Public License
     along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
 
-    Copyright 2017-2019 Telegram Systems LLP
+    Copyright 2017-2020 Telegram Systems LLP
 */
 #include "td/utils/port/detail/Epoll.h"
 
@@ -109,6 +109,7 @@ void Epoll::run(int timeout_ms) {
 #ifdef EPOLLRDHUP
     if (event->events & EPOLLRDHUP) {
       event->events &= ~EPOLLRDHUP;
+      flags = flags | PollFlags::Close();
       //      flags |= Fd::Close;
       // TODO
     }