Updated NEWS file
Reinstalled a single isargsecondarysource test function
Updated aliasing_frequency to work with secondary sources instead of dx0
Fixed comment
Updated rotation_matrix for the 3D case
Updated comments in driving functions
Switch default colormap to inverted gray
Added explanations for the zero padding in the driving function
Updated the 2.5D HRTF extrapolation to work with the new driving functions
Fixed a comment placing
Update driving_function_imp_wfs_25d.m
Updated the WFS prefilter
Slight updates and thoughts for the documentation of driving functions
Merge branch 'threed' of github.com:sfstoolbox/sfs into threed

* 'threed' of github.com:sfstoolbox/sfs:
  Update driving_function_imp_wfs_25d.m
  Fixed a comment placing
Updated NEWS file
Released version 0.2.3
Merge branch 'master' into threed

* master:
  Released version 0.2.3
  Updated NEWS file

Conflicts:
	NEWS
Cleaning up of driving_function_imp_wfs_25d.m
Added single driving functions for the different source models + conf.dimension
Cleaned up the wfs imp functions