Remove completely unused QUIT_DELETE_WORLD quit_status.
Change DELETE_WORLD option to only delete if no other characters.
cmake fixes

- Fixed up location if LICENSE.txt
- Adapted to new requirement of specifying both -DTILES and -DSDLTILES for tileset builds
Add capability to specify message context using pgettext(ctxt, msg).
Use pgettext for main menu options to fix ambiguous "<R>eset".
Explicitly initialize n to 0 in count_saves().
Print list of active characters when preventing deletion of world.
Merge delete world adjustment, pgettext, and cmake fixes.