Implement fetching of enabled features

Change-Id: I298a3ffeba4606bd0111460830e9ec60682e5f32
diff --git a/src/yang_schema.hpp b/src/yang_schema.hpp
index aa5faa4..14b0f1e 100644
--- a/src/yang_schema.hpp
+++ b/src/yang_schema.hpp
@@ -50,6 +50,9 @@
     /** @short Loads a module called moduleName. */
     void loadModule(const std::string& moduleName);
 
+    /** @short Enables a feature called featureName on a module called moduleName. */
+    void enableFeature(const std::string& moduleName, const std::string& featureName);
+
     /** @short Adds a new module passed as a YANG string. */
     void addSchemaString(const char* schema);