try to not include headers from headers, and remove some redundant include. This helps in modularizing the codebase and also helps during incremental compilations.

Now that all the queues are correctly initialised, there's no need for that dance.

in order to do so, we also have to export some internal variables from ui (the width and height of the window). Not the best possible outcome, but are used only in recompute_help, and can be dropped later. Also, move wrap_page to wrap.c.