Time-Consistent Localisation Seeking

[sbatchelder]

During video annotation, localisations are currently ordered by index. An option to use a re-ordered index list should be available, such that localisations are ordered according to their video-frame's ID (instead or localization's ID). This would enable a user to use FrameSeek:Auto and move through the localisations in linear-time. This re-ordering should apply both when Grouping is enabled and disabled.

[jrtcppv]

This is aligned with other user feedback we have received; however, we believe a broader rework of the entity browser is in order. We are thinking about UX changes that would include an expandable tabular view of entities that could be sorted by columns including frame number. Will update this issue when we have made more progress on the UX design activity.