exchange: add a new method to pull markers It has both local and wire protocol implementation. This command does not requires escaping of the marker and are expecting to me highly faster than the pushkey method. The other main point is that command is to accept a `heads` and `common` argument to select to pull changeset only relevant to a set a of node. We are not using this capability yet but we'll do it soon

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

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

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