libutils: add a binary blob cache implementation.

This change adds an implementation of a cache that stores key/value
pairs of unstructured binary blobs.

Change-Id: Idd01fdabedfa3aed6d359a6efb0592967af52651
diff --git a/libs/utils/Android.mk b/libs/utils/Android.mk
index e8d40ba..093189c 100644
--- a/libs/utils/Android.mk
+++ b/libs/utils/Android.mk
@@ -21,6 +21,7 @@
 	Asset.cpp \
 	AssetDir.cpp \
 	AssetManager.cpp \
+	BlobCache.cpp \
 	BufferedTextOutput.cpp \
 	CallStack.cpp \
 	Debug.cpp \