Checkpoint while standalone

[Nicolas]

Debugging checkpoint code can be hard if it requires running under the control of the core client, so it's often useful to make it checkpoint without caring about preferences when running as standalone. For example, making it checkpoint always​ if standalone (instead of calling boinc_time_to_checkpoint), but that causes too much I/O. It's much better to make it checkpoint at a fixed interval​

I suggest adding a feature inside boinc_time_to_checkpoint itself to return true every few seconds if running standalone. Maybe make it possible to change the checkpoint interval.

[Nicolas]

A really simple workaround: make it checkpoint always

[Nicolas]

Another workaround: if standalone, call a different function