[Stream] Rename (ReadableStream|WritableStream){ => Interface}

For the record, I disagree with this. But I will cry in my corner for this
one.

Author: igorw

Connection.php

@@ -4,7 +4,7 @@
 
 use Evenement\EventEmitter;
 use React\EventLoop\LoopInterface;
-use React\Stream\WritableStream;
+use React\Stream\WritableStreamInterface;
 use React\Stream\Buffer;
 use React\Stream\Stream;
 use React\Stream\Util;

ConnectionInterface.php

@@ -3,10 +3,10 @@
 namespace React\Socket;
 
 use Evenement\EventEmitterInterface;
-use React\Stream\ReadableStream;
-use React\Stream\WritableStream;
+use React\Stream\ReadableStreamInterface;
+use React\Stream\WritableStreamInterface;
 
-interface ConnectionInterface extends ReadableStream, WritableStream
+interface ConnectionInterface extends ReadableStreamInterface, WritableStreamInterface
 {
     public function getRemoteAddress();
 }