Chrash 7.3.7 VC++64 on loading project scripts with no-longer existing files

[douche]

Steps to reproduce:
* open avidemux, open file "A", save project script, close avidemux
* rename the file "A"
* open avidemux, load the project script; result "nothing happens" (a note would help)
* rename the file "A" back, load the project script, attach another file "B", save project script, close avidemux
* rename the file "A" again
* open avidemux, load the project script; result: chash with message

Assert failed :0 at line 341, file D:\jenkins\workspace\VS2015_no_import\avidemux\common\ADM_editor\src\ADM_segment.cpp

[douche]

... the same applies to the stripped debugger info for the MinGW builds, too.

[eumagga0x2a]

This is apparently a design decision (a very old one) not to distinguish between input from project script and the UI, which allows very much flexibility like the ability to mix script and command line. Some aspects of this design are not very friendly from a user's point of view, I must admit. Maybe some day a solution surfaces.