setenv.bat (and activate_venv/get_cmd/install_py.bat) had a UTF-8 BOM,
which cmd.exe read as part of the @echo off line, breaking every bin
script that calls setenv.bat via `call`. Stripped the BOM.
material_flow.bat/.sh and tro_flow.bat/.sh now check up front whether
the Graphviz engine --tosvg needs (dot, or neato with --use-cords) is
resolvable, and print an early WARNUNG with fix instructions if not -
before the CSV is even parsed. The Python scripts still run and report
the same failure in detail if the SVG step is actually reached.
m.stangl
fce0b8d9a1