Improve the Altering List pivot rule for NetworkSimplex (#435)
Much less candidate arcs are preserved from an iteration to the
next one and partial_sort() is used instead of heap operations.

 EXTRA_DIST += \

 	scripts/bib2dox.py \

 	scripts/bootstrap.sh \

 	scripts/chg-len.py \

 	scripts/mk-release.sh \

 	scripts/unify-sources.sh \

 	scripts/valgrind-wrapper.sh