Fix up Todo applet to work with new changes.

[adaburrows]

Make changes similar to the feed applet for renaming widget -> control.

[nick-stebbings]

See PR 26 in the todo applet neighbour-hoods/todo-applet#26

[nick-stebbings]

Maybe this needs to be its own issue, not sure, but in case not I will put it here:

Upon doing a bit of testing, there is still some issue with the applet currently building and how it is wired up to assessments (not easy to demo).

• Need to check if all assessments come through once the tray config is correct.

• What was an output-assessment-renderer previously, (which is now a star icon on the app) on the left of the task, which has been switched with another input-assesment-renderer (importance, using a star icon). This is fine except the config doesn't reflect this properly so the assessments coming through, after the configuration process, and the icons, which they need to be rendering in the assessment config edit screen, don't make sense.

• Probably we just need to go back over the config and deliberately create a good 'contrasting applet config' that shows off the features we have implemented in the most basic form on the applet dimension config dialog.

. It is partly due to having to change the Applet config in order to test this very complex setup for different combinations, that the Todo applet config has been changed and it might be better to look to an old-ish config file in the commit history to restore it to.

• I would like to recommend using the Feed applet as primary applet to demo with, then try adding this as a secondary one if need be, but know it's not as easy to set up with the current config.