- Uncaught Qt Script exception are now converted to a C++ exception of
type `CGAL::Three::Script_exception`.
- With `<CGAL/Three/exceptions.h>` and the use of `QScriptable` and
`CGAL::Three::wrap_a_call_to_cpp`, if a C++ exception is thrown by a C++
piece of code that was called from a script, then a Javascript
exception is thrown, so that a script can have a chance to catch it.
- Add a method `throw_exception()` in the `trivial_plugin`, as well as
test scripts in `javascript/tests/`, to test that new set of features
in C++/QtScript exceptions handling.