Various changes

Unfortunatly this pull request is kind of a mess, through the refactorings a lot of whitespace changes and superfluous library `use` changes where introduced. I'm sorry for that and will try to prevent such a thing in the future.

## Changes

* Renaming of `Box -> _Box`

Box is a reserved name in rust since 0.10, so we had to rename it to something. I think bbox is a bad name because it is often used for the gtk button box (as can be seen in the gtk source: https://git.gnome.org/browse/gtk+/tree/gtk/gtkbbox.c). So i decided to name it _box, i think this is the best name because it is minimizes the difference between the gtk name and the underscore does not have special meaning in rust (correct me if i'm wrong here)

* `Makefile` improvements

Various makefile improvements like rules for builiding documentation and overall better structured IMHO.

* Refactoring all of the sourcecode into the `src/` directory

* Moved the `rt` module into `gtk`

I believe this mimics the gtk api better: `gtk::init(); gtk::main()` also i renamed `_main*` to `main*` maybe there was a reason for this underscore that i overlooked?

* the glue library is now a static dependency (with appropriate changes to the Makefile).

* `macro.rs`

The only real change we made upping rgtk to rust 0.11 was in this file. I managed to get the some parts to work that you commented out. I don't really understand the code yet so i don't actually know which way was better.

Thanks,

-- Mathijs