Some code cleanup in matching.
Work on rfbucket generator.
RFBucket generator quite completed with different integration methods. Now we need more tests and an export function.
Study convolution for feedback and wakes.
Extend feedback by Gerd's function. Include convolution in wakes. Still to perform some tests.
Start redesing of wake fields. Some clean-up of particles.
Work in modifications in wake fields.
Wakes under development...
Merge branch 'kli' of https://github.com/like2000/PyHEADTAIL into rfq
Add changes made to property 'gamma' by oeftiger.
Replace slice and bunch statistics attributes by methods. Adapt monitors.
Restructure wake field implementation.

    - User generates wakes using wake_fields_3.py interface.
    - A wake source generates a list of wake kick objects.
    - Tracking is done in wake_fields_3.py for all the kick objects
      for all the wake sources that are provided by the user.
Open and close h5 monitor files at each 'dump' -> Data are stored even when simulation crashes.

  - No large performance penalty observed.
Variables z_index and first_particle_index_in_slice stored exactly the same information -> reduce to one.
Rename classmethod 'wake_table' -> 'table'.