excluded the Jastrow parameter corresponding to the largest distance on the lattice from the list of variational parameters (it is fixed to zero to provide a reference point for the stochastic reconfiguration optimization)
added the measurement of the Delta_k; fixed a bug that made the max distance irr idxrel wrong on the 2dsquare lattice
implemented the ObservableDeltaK class
implemented the ObservableDeltaKDeltaKPrime class
implemented the ObservableDeltaKEnergy class
initial implementation of the wavefunction optimization via the stochastic reconfiguration method
implemented a heuristic procedure to decrease the 'timestep' and increase the binlength during the stochastic reconfiguration optimization
improved stochastic reconfiguration routine (parameters now modifiable through the options); improved the UncertainQuantity template; fixed an issue where every Monte Carlo cycle of an optimization would use the same rng seed
implemented an observable cache to avoid calculating observables multiple times; tweaked the refinement during the SR cycle
added saving and loading of variational parameters
added two simulation modes: single run and SR optimization; minor cosmetic improvements
merged stochastic reconfiguration optimization from branch optsr