More improvements to cleaning

Makefile: separate clean and distclean
Makefile.ocpi.for-pkg: export PKGOBJECTS, reduce warnings in "clean"
components/cic_hpfilter_complex.test/Makefile: remove incorrect component library inclusion
components/cic_lpfilter_complex.test/Makefile: ditto
components/dds_complex.test/Makefile: ditto
components/fm_demod_complex.test/Makefile: dito
components/fsk_mod_complex.test/Makefile: ditto
components/genExpected.test/Makefile: ditto
components/mixer_complex.test/Makefile: ditto
components/noise_gen_complex.test/Makefile: ditto
components/sym_fir_complex.test/Makefile: ditto
components/sym_fir_real.test/Makefile: ditto
components/unit.test/Makefile: ditto
tools/cdk/include/hdl/hdl-pre.mk: reduce clutter of messages under "clean"
tools/cdk/include/lib.mk: don't clean HDL components under make clean
tools/cdk/include/package.mk: reduce clutter of messages under "clean"