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.
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 master with changes by Hannes in bunch, slices, matching. Update grid.
Merge branch 'kli' of https://github.com/like2000/PyHeadTail into kli
First version of integrated Green's function. Tidy up bunch constructors.
Add stride information to particle monitor.
Merge branch 'kli' of http://github.com/like2000/PyHeadTail into kli
Clean-up ParticleMonitor; remove sort function.
Continue work on Poisson solver; slight correction in monitors.