Improve renderscript context teardown.  Track object in the system and then force their cleanup by releasing all user references once destroy context is called.  Java layer will no longer send destroy notifications for objects garbage collected once a context is destroyed.
diff --git a/rsSampler.h b/rsSampler.h
index 4b504f6..ccf9b4d 100644
--- a/rsSampler.h
+++ b/rsSampler.h
@@ -31,7 +31,8 @@
 class Sampler : public ObjectBase
 {
 public:
-    Sampler(RsSamplerValue magFilter,
+    Sampler(Context *,
+            RsSamplerValue magFilter,
             RsSamplerValue minFilter,
             RsSamplerValue wrapS,
             RsSamplerValue wrapT,
@@ -55,12 +56,12 @@
     int32_t mBoundSlot;
 
 private:
-    Sampler();
+    Sampler(Context *);
 
 };
 
 
-class SamplerState 
+class SamplerState
 {
 public: