feat(lookup): LUTs and context to make better docs

Now a context is passed to utility functions, which contains the state
these may be interested in. This keeps it clean from global state.

With the lookup tables, it is possible to figure out relations between
types and document them accordingly.

gen/youtube3/README.md

@@ -3,6 +3,9 @@ The `youtube3` library allows access to all features of *YouTube*.
 TODO: Library level fully fledged documentation, incuding **summary** and **usage**.
 And another line, for testing
 
+# Activities
+
+
 # License
 The **youtube3** library was generated by Sebastian Thiel, and is placed 
 under the *MIT* license.