Fix <defunct> CubicEvaporationPolicy integration

[mfrey]

We should fix the integration of class CubicEvaporationPolicy in the framework. The class provides the functionality for a cubic evaporation but the expected parameter settings have slightly changed.

[fgrosse]

Sorry I constantly forgot to create this issue. Here a more detailed description on what is missing:

As far as we have thought about this, the cubic evaporation should only be applied whenever there is no traffic routed over the node. This means that the client need to remember when they have lately relayed traffic and apply the cubic evaporation according to this point in time. Now that I think about it, that is kind of what we do already with our implementation of the evaporation on the routing table. We need to look into it and maybe adjust our logic accordingly.