Add RuntimePermissions sample.

It shows use of runtime permissions API in M.

Change-Id: I29a1271186c2664a20f183b327ce6be25feec78f
diff --git a/system/RuntimePermissions/settings.gradle b/system/RuntimePermissions/settings.gradle
new file mode 100644
index 0000000..9464a35
--- /dev/null
+++ b/system/RuntimePermissions/settings.gradle
@@ -0,0 +1 @@
+include 'Application'