topics: add a config to reject draft changeset without topic on a server This patch adds a new config option experimental.topic-mode.server which if sets to True, the server won't accept any draft changeset without topic on it. In case both `experimental.topic-mode.server` and `experimental.topic.publish-bare-branch` are set to True, the enforce-topic one is respected. Tests are added for it. The CHANGELOG file is also updated mentioning about the config option.

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