Log Message:
Update clutter-box2d to 0.8.2.

clutter-box2d-0.8.2:
====================

Changes:

  - Fixed bug in prismatic joint constructor.
  - Updated box2d version used.
  - Updated and improved documentation.
  - Updated and improved parameter handling in public API
    entry points.
  - Added support for callbacks for collisions.
  - Bug fixes relating to reference keeping.
  - Brought sandbox testbed app up to date with API changes.