Several updates, fixes and additions (TcpClient, MtProto...)

README.md was updated to reflect more useful information
More errors from the official Telegrm website have been added
MtProtoSender now handles updates (and doesn't crash!)
Fixes on TcpClient to be able to receive whole large packets
Updated scheme.tl to the layer 55
Session is now saved more often (to prevent damages from crashes)
Fixes to the code generator (generated invalid code for reading "bytes")

network/tcp_client.py

@@ -23,4 +23,11 @@ class TcpClient:
 
     def read(self, buffer_size):
         """Reads (receives) the specified bytes from the connected peer"""
-        return self.socket.recv(buffer_size)
+        # TODO improve (don't cast to list, use a mutable byte list instead or similar, see recv_into)
+        result = []
+        while len(result) < buffer_size:
+            left_data = buffer_size - len(result)
+            partial = self.socket.recv(left_data)
+            result.extend(list(partial))
+
+        return bytes(result)