Revert "Begin implementing calendar event reminders to replace the rudimental "Set event chrono" functionality."
After a lot of (uncommitted) coding, I realized that all and any reminder system would end up being as bad or worse than the chrono system. It would be very hard not to make the code miss reminders, without having lots of events at once in memory. To have many reminders at once, one would need to use the SMEM, but one can't always be reading it without making UX worse. One could cache, but for that we need a lot of RAM which we don't have. A lot of work and many structural changes for little results.
Event reminders is one of those things that will need to be thought from the start, if I ever decide to adopt a new event database system.