evolve: fix stabilization of orphan merge changesets in case of conflicts As demonstrated by tests added in previous patch, if one of the parent of a merge changeset has a new version and merge changeset gets, running `hg evolve` to stabilize that if results in conflicts will lead to lose of other parent of that merge changeset when we resolve conflicts and do `hg evolve --continue`. This patch fixes the behavior, by checking whether we are continuing evolving a merge changeset and if yes, setting the dirstate parents according to that.

all: tutorials/tutorial.rst tutorials/topic-tutorial.rst static/logo-evolve.ico
	sphinx-build . ../html/

tutorials/tutorial.rst: tutorials/tutorial.t test2rst.py
	python test2rst.py tutorials/

tutorials/topic-tutorial.rst: tutorials/topic-tutorial.t test2rst.py
	python test2rst.py tutorials/

static/logo-evolve.ico: static/logo-evolve.svg
	convert -resize 36x36 static/logo-evolve.svg static/logo-evolve.ico