PhysiCell_settings-backup.xml concept is broken

[elmbeech]

the Makefile reset function relies on a PhysiCell_settings-backup.xml file.
the problem is that not all sample project generate aPhysiCell_settings-backup.xml.
the bigger problem is that Makefile load function not generate at PhysiCell_settings-backup.xml.

as far as I can see, the PhysiCell_settings-backup.xml is only used by the reset function.

in my opinion, it would be wiser to have similar to the sample_projects/Makefile-default a sample_projects/PhysiCell_settings.xml-default and use this for the reset function.

[elmbeech]

The basic problem is now resolved in this pull request #244.
The Makefile reset function uses now sample_projects/PhysiCell_settings.xml-default to restore the initial condition.

I did not look into why some sample projects do make a PhysiCell_settings-backup.xml and some don't.
In my opinion, backups should be there just for safety. No code should rely on backups.