improve error reporting and handling

Currently, some assertions seem to be used as a way to report unlikely events, and when these are used in production, they can cause needless crashes (even though they're then handled by systemd's Restart=on-abnormal facility)

I propose the following changes:

• The code should not rely on assertions, if it does, it's a bug that should be fixed.
• Errors, even unlikely ones (currently handled by assertions) should be logged properly.
• There could be an option (off by default) to enable reporting these remotely.