Configurable topology

[alessandropellegrini]

We need to implement a configuration API for the topology library which allows to initialize and evolve at runtime an arbitrary topology, based on exit probability from a cell LP.
This should be stored into the LP platform-level (as per issue #8) state, since this should be rolled back as well.

At this point, it is unclear whether it is more efficient to handle the initialization of this matrix by a single LP (e.g., lid 0) during the execution of INIT, if all LPs should initialize by themselves, or if this should be provided as a configuration file.

Possibly, all these solutions are worth to be implemented, as they could serve different goals.

[alessandropellegrini]

Moved to 2.0.0 as this is almost finally implemented.