Verfishd

This Release:

- improves the performance of the simulation dramatically
- add the possibility to continue the simulation
- adds a more versatile `.plot` function to the `VerFishDModel` class and additional functions to plot only parts of the result (Evaluation Function, Stimuli Profile or the Distribution itself).

This is the initial Release with the basic structure the library should follow.

It's already possible to do simple simulations. Nothing fancy regarding the use of complex physical factors is currently possible. The plotting feature is more of a work in progress and the .cnv import needs some polishing.