gen_gerber_and_drill_files_board.py:
* fix to make it compatible with rev 6280.
* allow this script to create files in the current plot folder defined from the board forder, no more only in current working directory.
Important note: from a python script one cannot plot the palge layout, because the page layout template file is not stored in the board file, but it is part of the project.
Because when using a python script, the project is not loaded, the page layout template is not known.
Trying to plot it crashes the script.