Commented the ClutterScript example so it can be used
inline as part of the recipe, rather than as an
example in the appendix (it's too simple to warrant
a separate appendix).
There was too much in the example code to cover in a single
recipe, so I trimmed it down to demonstrate simple
UI building (no constraints, effects, animations, or signals).
Added a simple script and program to load it, to support
recipe on ClutterScript for UI definitions.
Also amended the Makefile (following the pattern of
the tests/interactive Makefile) to enable signal
connection from ClutterScript by passing -export-dynamic
to linker.
