@export: add export_parent

1. export_parent is by default true
2. setting export_parent to false will prevent -Lexport-header from
exporting hal information

Fix: 32539339
Test: verification that output without adding the option is the same,
manual test with export_parent = true/false
Change-Id: I7a6304cdc40a495427d0369fcc054675770df608
diff --git a/Annotation.h b/Annotation.h
index 063b8e4..18d9ab0 100644
--- a/Annotation.h
+++ b/Annotation.h
@@ -37,6 +37,14 @@
     const std::string &getName() const;
     const std::vector<std::string> *getValues() const;
 
+    const std::string &getSingleValue() const;
+
+    /* Returns unquoted version of getSingleValue */
+    std::string getSingleString() const;
+
+    /* Returns value interpretted as a boolean */
+    bool getSingleBool() const;
+
 private:
     const std::string mName;
     std::vector<std::string> *mValues;