Add SignTos tool

Change-Id: Iac7db75cda383e333a55236c3678cd56f8245d6e
diff --git a/tools/signtos/SignTos.mf b/tools/signtos/SignTos.mf
new file mode 100644
index 0000000..d860296
--- /dev/null
+++ b/tools/signtos/SignTos.mf
@@ -0,0 +1 @@
+Main-Class: com.android.signtos.SignTos