* Add Process.getProperty, Host.getProperty, Host.getProperty: allows
you to retrieve the properties of the processes/hosts
* Deprecate Msg.clean(): you can just forget about it now.
+ * New function Process.getCount(), that only works when compiling
+ with the not yet released version 3.9 of the C library.
* New context factory based on Coroutines. It mandates a modified JVM
but then, the simulations run about five times faster, and there is