before_script errors return full path to file.
Assure the sphinx is below version 1.2.1, sphinxcontrib-aafig will give a failure until it's patched
before_script: with ./ at the beginning will load relative to tmuxp
file (project root). same behavior as start_directory. Some comments
on how .expand()'s cwd argument is the project's config file dir when
loading via cli.