Rename mash_shell to mash_session.

mash/session/main.cc

Index: mash/session/main.cc
diff --git a/mash/shell/main.cc b/mash/session/main.cc
similarity index 72%
rename from mash/shell/main.cc
rename to mash/session/main.cc
index 06cdc36f5cb42693bedcd8123f0b48d580fb34de..1ca0f5b8ac243df4cf90f84213242388893f88cf 100644
--- a/mash/shell/main.cc
+++ b/mash/session/main.cc
@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "mash/shell/shell_application_delegate.h"
+#include "mash/session/session.h"
 #include "mojo/public/c/system/main.h"
 #include "mojo/shell/public/cpp/application_runner.h"
 
 MojoResult MojoMain(MojoHandle shell_handle) {
-  mojo::ApplicationRunner runner(new mash::shell::ShellApplicationDelegate);
+  mojo::ApplicationRunner runner(new mash::session::Session);
   return runner.Run(shell_handle);
 }