[Feature Request] Allow task rerolls for more casual taskers

[RedSparr0w]

Not everyone using the plugin is a task locked account,
I think it would be nice to add a re-roll option for unofficial taskman.

Config option:
(Enable rerolls) if set to 0 (default) rerolls will be disabled

Unsure if it should reset back to maximum rerolls or just go up by 1 for each task completed.

[rmobis]

Pulling LMS out of this issue and into #69 because that is an exception supported by the official rules.