v0.2.0

New features

• Added the An-Schorfheide model, a simple three-equation New Keynesian model.
• Added Model 1010, an updated version of Model 1002.
• Added three optimization methods: :simulated_annealing, :LBFGS, and
  :combined_optimizer (which alternates between simulated annealing and
  LBFGS).
• Added the PseudoObservable type and the pseudo_measurement function, which
  defines pseudo-observables (linear combinations of states which are not
  observed) for each model, e.g. the output gap.
• Implemented the forecast step, a suite of functions that forecast using
  estimated parameters and compute means and bands of the forecasted series. The
  top-level functions are forecast_one and means_bands_all; see the
  forecasting and
  means and bands
  for more details.

Breaking changes

• Added the Observable type; replaced the data_series and data_transforms
  fields in the model type definitions with
  observable_mappings::OrderedDict{Symbol, Observable}, which is initialized
  in init_observable_mappings!.
• kalman_filter has been broken out into
  StateSpaceRoutines.jl.
• estimate now saves only parameter draws, not the associated state-space
  matrices or the last filtered states for each draw.