Missing init method in AdditionalEquations interface
We can't initialize the equations in AdditionalEquations interface with
a method init. MainStateEquations interface has a method init,
So, it can be usefull to implement this method in AdditionalEquations
interface because Hipparchus can call it.
(from redmine: issue id 401, created on 2018-03-15, closed on 2018-06-04)