Roughly in order of importance.                                     -*-org-*-

* Make kwant run on windows

* Implement "lead freezing"

* Add calculation of current density

* Consider making the b parameter of _solve_linear_sys a matrix instead of a
  list of matrices

* Find a nice way to organize / deal with ldos or wave_func output when the
  number of orbitals per site varies

* Add a (tutorial?) example with kwant.plotter.map

* fix physics.noise (docstring, __all__, etc.)

* Verify that selective plotting works.

* Write an RGF solver that uses graph/slicer.

* Add support for easily adding magnetic field to a system.

* Allow plotting of infinite systems

* Use sparse linear algebra to calculate bands
  However, SciPy's sparse eigenvalues don't seem to work well.

* Allow attaching leads with further than nearest slice hoppings.
  The most easy way to do this is increasing the period of the lead.
  Alternatively, generalize modes and InfiniteSystem format.

* Benchmark MUMPS and check whether nested dissection would be useful.
  If yes, implement it.

* Make kwant objects pickleable.

* "shape" doesn't work for leads when only checking y (and not x)
  Make it aware of symmetries.

* Improve experience when working with sites in a finalized builder
  (It should be possible to map sites to nodes efficiently.  Probably, the best
  way to do it is to sort the sites in finalized builders.)
  One could than also RLE compress sites in finalized builders.

* In finalized leads, only keep the sites of the slice.

* Generalize InfiniteSystem to multiple directions.

* Add support for optimization of lead fundamental domains.

* Write a module to generate "functional" random numbers.
  That module should probably use (hardware accelerated) AES encryption.

* Incorprorate efficient correlated disorder using scipy.spatial.

* Implement the C solver interface.

* Wrap TB_SIM as a solver.

* Implement models module, incorporate units into it.

* Improve handling of s-matrices with important additional degrees of freedom.
  i.e. spin, or electron-hole.  Currently, one needs to manually process lead
  modes and to perform a basis transformation of the scattering matrix.

* Implement automatic search for discrete symmetries of a tight binding model
  and of conservation laws.

* Revisit Symmetry, make it more general. I.e. allow for description of other
  discrete symmetries, possibly also symmetries which change site and hopping
  values (=gauge symmetries).