Otherwise some message handlers might be thrown off by seeing a trigger
that's actually just the quoted part of a previous message.
The full message body is still always available via the event property.
The post filter is kept very simple, it works by checking if a fixed
string exists in the configured field. This could easily be expanded
allowing for regex or even more complex filters like date-time
comparisons.
The urlinfo plugin is now set up to look up URL information for any URL
occurring in text, not only when triggered explicitly as a command.
The youtube plugin should probably be integrated into this setup,
replacing the bot plugin with a urlinfo extension.
