Allow the active column to be a sortable field.

Current situation:
The 'active' column is not a valid sort field.

Suggested Improvement:
Allow active to be a sortable field.

Why?
Let's say I have a list of tasks, I'd like to ensure that the active task, the one I started with task start .. always shows up at the top. There might be more important tasks I could be working on, but I like not to have to hunt around for my active task in a list of tasks. And yes I know task active exists... but when I come up with my filter for the day's tasks its nice to be able to check in and remind myself what I *should* be doing (along will the metricds I track in terms of elapsed time etc)...

Thanks!