In track method of cavity resonator, there was an additional phasor decay of bin length.
To avoid that the good boundaries are set bins[0] instead of center[0].
For now the bins are also shared in Beam.mpi_share_distributions

Add single core tracking for CavityResonator
Correct missing ref_frame is CavityResonator.track
Change phase of generator voltage to be the bin phase
Correct generator phase for non integer m
Change init_phasor track time to 10 times
Change phasor_evolution k to change order of steps

Add phasor initialization (on the "rf" reference)
Change beam phasor evolution to allow for "beam" or "rf" reference

Correct case when where is no mp in the bin
Remove useless test

Add tracking to CavityResonator based on the mbtrack implementation but using a analytic formula for speed-up
Add method to Beam to share longitudinal distributions
Add methods to Mpi to look for next and previous bunches
Add start of a CavityMonitor, to improve to deal with multi-cores

Add CavityResonator class
Add BeamLoadingVlasov class, to do tested and developped further.
From BeamLoadingVlasov, only the beam_equilibrium method is well tested and benchmarked.
The cannonical_transform and solveB methods have to be tested and benchmarked further.

Remove tools.py to avoid circular import problem with wakefield.py -> merged into wakefield.py
Remove machines folder to save machine data in a seperate git instance
Rework import so the code can be used as independant module mbtrack2

Update machines/__init__.py, machines/soleil.py, tracking/__init__.py, tracking/aperture.py, tracking/element.py, tracking/optics.py, tracking/parallel.py, tracking/particles.py, tracking/rf.py, tracking/synchrotron.py files

To be PEP8 complient:
Lowercase folders
Extended docstrings
Rename and divide some files