Started reorganizing bunch.
Cleaned up bunch; reorganized slices and matching.
Separated matching and slices out of bunch class. Slimmed down bunch class.
Some minor bugfixes in matching.
Added gsl random numbers; still need to fix gaussion generation via qrng. Require CythonGSL.
Added random.pyx.
Initiated poisson solver development; started grid construction.
Working on Poisson solver.
Replace-merge from branch kli.
Replace cobra_functions with stats.
Remove cobra_functions.
Replaced cobra_functions by stats.
Working on gather function on grid.
Working on gather function on grid.
Working on gather function on grid. Added  histogramming for nearest neighbour interpolation.
Continue work on Poisson solver, make density on grid with nearest neighbour interpolation. Add id to bunch.
Merge from HBartosik with changes in bunch, slices, matching. Add new wakfields.
Merge branch 'HBartosik'; correct sign error in constant_wake_factor.
Merge from master with changes by Hannes in bunch, slices, matching. Update grid.
Merge branch 'kli' of https://github.com/like2000/PyHeadTail into kli