Using Tidy widgets within gnome-shell

[Owen Taylor <otaylor redhat com>]

We wanted to do some experimentation with using Tidy widgets within
gnome-shell. Tidy is described in:
http://www.clutter-project.org/blog/?p=41.

It's not completely clear what exactly in Tidy is useful for us at
the moment, but it's pretty foreseeable that *something* from
there will be useful in the future.

How the build works
===================
The imported tidy widgets are built into a libtool convenience library,
and that is then directly imported into libgnome-shell (our shared
library plugin)

We run g-ir-scanner on this *twice*, once to build Shell.typelib and
once to build Tidy.typelib; both typelibs point to the same shared
object but look distinct from Javascript.

How to use 
==========
The obvious way:

  Tidy = import.gi.Tidy;

  button = new Tidy.Button({ label: "Hello World" });

How to add more stuff
=====================
What I imported initially was TidyButton, TidyFrame, and TidyGrid, with
their dependencies.

To add something else:

 Copy the source files from the tidy tree into gnome-shell/src/tidy
 Add the .c and .h files to the obvious place
    in gnome-shell/src/Makefile.am

Type 'make'.