int and unsigned int parameters warnings

The current implementation of the ParameterServer and the converter (actually only this last one) does not check if the user provided a parameter with the correct type. Only casts the parameter to the type.

Then, a user can provide a double for an int parameter, the value will be casted to an int and it won't be warned about it.

In case of an unsigned int, if a user provides a negative number, the casting will just set the parameter with a hugh positive number without raising any warning. (This was happening in hello_wolf, in the yaml a TreeManagerSlidingWindow was defined with n_frames = -1 which is not allowed since it is an unsigned int).

I do not know if we want to throw an error or just a warning/error message. In this stage, several messages are printed... maybe we should throw an error.