Refactor reactive socket implementation so that synchronous read, write,

accept and connect operations don't modify data associated with the socket.


[SVN r48491]

libs/asio

@@ -1 +1 @@
-Subproject commit 2f86d9c815e61db8c1d9f6b056cbb6bac1b186fe
+Subproject commit 7176a41d0d188b2c44536af1474e55082ae60e8f