Totally refactored source files location

Now it *should* be easier to turn Telethon
into a pip package

telethon/network/__init__.py

@@ -0,0 +1,5 @@
+from .mtproto_plain_sender import MtProtoPlainSender
+from .tcp_client import TcpClient
+from .authenticator import do_authentication
+from .mtproto_sender import MtProtoSender
+from .tcp_transport import TcpTransport