bugfix: increase population by number of worker groups; arguments as members to avoid multiple getarg calls

extend multi-slit language to support bitmap masks; Binary pbms not parsed correctly yet, working on it

IPPL/FFT cleanup:
- header added to file
- obsolete files removed
- line indentation fixed
- required functions and macros moved from c_utils.{c,h} moved to fftpack.cpp

renaming Collimator to CCollimator where C stands for cyclotron; all other collimators are implemented using FlexibleCollimator; This also fixes #224

first version of multi-slit/pepperpot/what ever aka flexible collimator. However way to slow to be practical

update required cmake version to 3.1 after change in 0e771d47; cleanup: cmake version only required at top level

using affine transformation instead of coordinate transformation. This allows for shear and perspective operations (to be implemented).

first draft of 'MultiSlitLanguage'; action has to be developed yet; goal is to have a vector of basic shapes (rectangle and ellipse sofar) with corresponding coordinate transformations