This tries to add information about when each option was added. It goes
back to version 183.
The version info is included from a separate file to allow generating it,
which would allow more control on the formatting of the final output.
- add reference to the service unit in the man page,
- fix several indentation and typos,
- replace '(uint64_t) -1' with 'UINT64_MAX',
- drop unnecessary 'continue'.