Review in Editor via IncRem List - Implement Done button and Next/Done shortcuts

[hugomarins]

Also add a warning when the user clicks "Review in Editor" without filtering by "Due" in the IncRem List.

[hugomarins]

The "Done" button and the warning in the IncRem list have been implemented, as documented in the Changelog.

All that is missing are the Next/Done shortcuts. For this, I'll have to modify the existing commands, to detect if we are in the timer review, and act accordingly.