[doc] fix reference to ~src/cubes in tutorial
~src/cubes refer to the $HOME/cubes directory of "src" user while ~/src/cubes
refer to $HOME/src/cubes directory of current user.
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