None-existent default project - exit on startup

[saroun]

Simres exits when a non-existent project is deifned in %userprofile%/.simres/user_projects.xml. Observed when migrating to 64 bit version after removing the 32-bit one.
Quick workaround: edit %userprofile%/.simres/user_projects.xml and define an existing project as the default (current=yes).
Solution: handle exception and (a) return to the selection dialog or choose a demo project by default.