Separate obj func

In this branch a new objective function has been developed. It can get outflow, ET and TWS data in the objective function from separated mHM calls. Therefore an index array had to be provided and is an optional parameter passed to every eval subroutine now. With this index array only the domains with the corresponding indices are simulated in that run.

The new objective function creates a disjunct partition of all indices, then calls mHM several times for each seperate subset of indices. Then it calculates an objective from all the simulated data. It is not a useful objective function in terms of science yet, but it is a useful sceleton.