Update to the last ncollide api.

For most algebra-related types, type parametrization has been replaced
by conditional compilation.  This means that most types are no longer
parametrized and compilation time/memory of user api is much lower.
Performances are unchanged.

Those changes exibited a bug on the island-based sleeping manager. It
has been deactivated until a proper fix is done.

Fix #3.
@mut is dead, long live @mut!
Fix the island-based activation manager.