#178 Finishing touches for Wigner transformation
#178 Wigner transform handles odd grid points correctly
#178 Added Wigner transform of density operators
#178 Doubled grid density of Wigner function
#178 Fixed Wigner transformation
#178 Step 2: Inverse Fourier transform, phase factors and such.
#178 Step 1: transform wave function into a rotated density matrix
#178 Added a helper function that gives the momentum range on which the Wigner transform is given.
Added non-functional parts of Wigner transformation
#178 Added a transformation for calculating reduced densities
#256 Updated NEWS
#256 Added functionality to add/subtract numbers to/from a state
#245 Fixed missing include
#245 updated Changelog
#245 Forgot to show the plot
#245 Fixed problems with propagation
#245 Fixed syntax errors in demo
#245 Finished first draft of NonMarkovian demo
#245 Started work on NonMarkovian demo
#245 Refactored Thermal density demo to use solvers directly.
#245 Updated documentation
#245 Adjusted demos to API changes
#245 Got acceptance tests to work again
#245 Updated the various factories
#245 Re-added remaining propagator code
#245 updated propagator to work with normal states instead of vectors
#245 Updated Python plotting observers
#245 Converted remaining observers to consider only a single state
#245 Got half of the observers to work again
#245 Updated filters to work with a single state only
#245 Finished OdeSolver
#245 Finished implementation of propagation
#245 Fixed crash
#245 Implemented framework for propagating single states
#245 added an OdeSolver; unfinished
#245 renamed OdeSolver -> OdeEquationSystemSolver
#245 enabled OdeSolver again
#245 converted FaberSolver to work with new interface
#245 enabled FaberSolver again
#245 Split off the equation system part into an own interface
#245 Converted ChebychevSolver to new scheme
#245 Converted ChebychevRelaxation to new interface
#245 Enabled compilation of Chebychev solvers again
#245 Adapted Solver interface to new concept of StateWithAuxiliaries
#245 Renamed 'Ghosts' to 'Auxiliaries'
#245 Updated Python interface for EquationSystem
#245 minor renamings
#245 Restricted EquationSystem to a single grid
#245 Made EquationSystem work with StateWithGhosts
#245 Allowed a StateWithGhosts to be constructed from Wavefunctions
#245 Commenting out all code that contains propagator functionality
#245 Added a basic test for the Python interface of StateWithGhosts
#245 Added new class StateWithGhosts
#194 updated NEWS
#194 renamed PropagatorIntegrationTest -> SolverIntegrationTest
#194 : removed some obsoleted solver attributes
#194 Some refactoring
#194 Renamed timestep -> dt as parameter and attribute
#194 Updated the tutorials with the code changes
#194 Updated demos
#194 Updated Python interface with latest changes
#194 updated Python interface
#194 Removed setTimestep() from solvers / made private
#194 added getTimestep() function
#194: Solvers get their timestep in constructor