improved results_????.bin - reading subroutines to get the whole data

- meanvalues, doublecorr, tripecorr quadruplecorr and mean_invar can now be independently read from the files,
  as it is happening within INCA
- renamed some variables: nstats->nsv, ncorrelations?->nsv?
- added OVER and COMBINATION functions
- cosmetics
added support for the additional field within result files + bugfixes in 2DPOST routines
major rewiring of the logic how to handle the data coming from result files

- first, instantaneous post-processing happens
- then, there is room for post-processing working on the not-averaged statistical values from INCA
- then, truely averaging is performed by the new subroutine HOMOGENIZE_DATA
- and finally, 1D and 2D post-processing happens on the averaged data
cosmetics / code consistency
major bump of 2D statistics to compute boundary layer thickness properties based on vorticity criterion

- use vor_ref_pos in &FLOW-namelist to control where delta_0 == delta_0_vort should be imposed
- the reference vorticity vort_ref_level is computed there and based upon this value, the thicknesses alonge the plate are computed
proper deallocation & public/private interface bugfix
Merge branch 'refs/heads/feature/delta_vorticity' into feature/resultfiles
Merge branch 'refs/heads/feature/resultfiles' into develop