Add the PlatformLibrary sample to the new "sample" vendor

This adds the PlatformLibrary samples previously located in development/samples.
This also creates all the files required to build an add-on including the optional
library provided by PlatformLibrary
diff --git a/frameworks/Android.mk b/frameworks/Android.mk
new file mode 100644
index 0000000..5053e7d
--- /dev/null
+++ b/frameworks/Android.mk
@@ -0,0 +1 @@
+include $(call all-subdir-makefiles)