GitLab

* fix typo introduced into tar_em_up.sh
* remove flext and rtcmix from LIB_TARGETS
* selectively compile disis classes on Windows
* use Program Files (x86) for win64

remove dependence on libiberty for mingw in Makefile (not sure whether Cyrille will do this upstream)

moved cwiid and all disis libs except disis_munger to externals/disis, and removed linux-specific build instructions from tar_em_up.sh

begin porting the disis_* dirs to a single library in externals/, starting with disis_phasor~.c.  We're just using the most recent version of pdlibbuilder to do the heavy lifting.