Remove ANNOT_CHANGED signal from libview, and create widget for annotations
Depends !191 (merged)
@camelCaseNick you may want to have a look at the new widget, and see if I should do something different.
@crab2313 I was very close to actually implementing the widget in rust, but I got a bit lost with the properties. I think it might be ready to be ported. Which widget would you consider the simplest one to look at, that has some properties?
Helps #137