[tox] Install "pyramid" dependencies in "doc" environment
Otherwise most of the cubicweb.pyramid API doc fails to build. For this we
skip installation in the "doc" environment and source the new
requirements/doc.txt which will install cubicweb[pyramid], thus pulling
cubicweb plus pyramid's dependencies.
Furthermore this requirements/doc.txt would be useful to build to
documentation on readthedocs.
missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules)
embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js