Added conf.ir.useinterpolation to config
Updated the ir interpolation
Enforced the interpolation warning for 3D, because it is not tested
Added the source weights as 7 column to x0
Added integrational weights
Fixed return values in tapering_window
Fixed a comment typo
Fixed a bug in generic_wfs() regarding the mapping of secondary sources
Simplified the functions to create IRs for the generic renderer
Added extra function for tapering of secondary sources

The value of the tapering window is now directly applied to the weighting stored
in x0(:,7)
Moved generic_wfs() to the SFS_ir folder
Moved ls_activity into x0(:,7)