Ability to update config.txt/projects.txt while the program is running

[rokstrnisa]

This issue was raised by Marcus.

There are at least two approaches to this:

1. The program listens for file changes (passively, with OS support).
2. The program re-reads the file(s) when told so (button, menu).

The latter option is more easy to implement robustly (not sure), and will not result in accidental reads.

[rokstrnisa]

This issue now loses some priority, since it's possible to add and delete projects using a GUI now.