Add external annotations database prebuilt

Change-Id: I41882744d9b0edbd2dd22ca0f22099cbb027a672
diff --git a/sdk-annotations/README.txt b/sdk-annotations/README.txt
new file mode 100644
index 0000000..61620ac
--- /dev/null
+++ b/sdk-annotations/README.txt
@@ -0,0 +1,6 @@
+Generated from tools/adt/idea CL
+I1b3cdaf5de8e9f857b786eb8e60c648289594d9b
+
+(by building the Android Studio tree by running ant
+in tools/idea, then copying the resulting androidAnnotations.jar
+as this annotations.zip file.)