XFAIL all the sio tests

They have random failures still, sadly.

src/test/run-pass/sio-client.rs

@@ -1,3 +1,7 @@
+// xfail-stage1
+// xfail-stage2
+// xfail-stage3
+
 use std;
 import std::sio;
 import std::task;

src/test/run-pass/sio-ctx.rs

@@ -1,3 +1,7 @@
+// xfail-stage1
+// xfail-stage2
+// xfail-stage3
+
 use std;
 import std::sio;
 

src/test/run-pass/sio-read.rs

@@ -1,3 +1,7 @@
+// xfail-stage1
+// xfail-stage2
+// xfail-stage3
+
 use std;
 import std::sio;
 import std::task;

src/test/run-pass/sio-srv.rs

@@ -1,3 +1,7 @@
+// xfail-stage1
+// xfail-stage2
+// xfail-stage3
+
 use std;
 import std::sio;
 

src/test/run-pass/sio-write.rs

@@ -1,3 +1,7 @@
+// xfail-stage1
+// xfail-stage2
+// xfail-stage3
+
 use std;
 import std::sio;
 import std::task;