correct slices.slice_constant_charge, center the binning around bunch.mean_dz, implement multiple longitudinal resonators (by passing the resonators as array)
Touch up bunch; work on Poisson solver; add cython functions for grid computations.
Looks like working particle distribution in grid_functions.pyx.
Add compute_potential_fgreenm2m.pyx.
Remove green_m2m_old.pyx.
Implement density computation using histogram.
Extend beam module by base and new derived classes.
Work on bunch.py e-cloud implementation and add some minor cosmetics.
Add scatter to grid_functions.pyx and implement pusher in solvers.
prepare for fixed slices option, some fixes in bunch.slices, change BenchMark_BBresonator_longitudinal.py to precomupute wakefunction from BB resonator and use the interpolated wake table
Record intermediate status in implementation of poisson solver; runnign example, poisson structure implemented via injection.
Add slimmed down bunch monitor.
Add fields calculation to Poisson solver.
Add some suggestions for an improved structure.
Merge branch 'HBartosik' of https://github.com/like2000/PyHeadTail into kli
Add new compact particle monitor.
Successfully benchmark Poisson solver.
Revised longitudinal tracking: integrated the libintegr.py integrator suite into longitudinal tracking.
It has been benchmarked against the former 3 integration mechanisms (exactly the same numbers are obtained!).
Alongside with a few precision improvements in various parts, the libTPSA library has been provided (needed since libintegr.py supports checking integration mechanisms for symplecticity).
Add p2m in compute_potential.pyx
Merge remote-tracking branch 'origin/kli' into alasheen

Conflicts:
	BenchMark_BBresonator_longitudinal.py
	main.py