This proposes a *new method* on IObservatoryCore: `SetGridItems(worker, items)` which does 2 things:
* Clears the grid
* Adds the given items.
Effectively replaces the entire content of the grid -- which is something a handful of plugins now do.
Why add this when you could just call Core's Clear + AddGridItems methods?? So it can all be done within the same rendering suppression "scope" to reduce flickering and increase rendering speed. Speaking of rendering suppression, I have implemented such rendering suppression "scope" which uses Listview's built-in Begin/EndUpdate() in combination with temporary removal of the sort comparer (as is done for read-alls). This was also applied to the existing AddGridItems(worker, items) method as well, addressing a TODO.
Add checkboxes to the PluginList which allow you to enable/disable each plugin on-the-fly (it will no longer respond to events, but you can still configure it, etc.). These settings are preserved in a new Core setting. Also enabled full-row select for easier selection in the listview.
Also increased the height of the PluginList slightly. (Personally, I'd like it even taller.)
Also made slight sizing adjustments to the plugin tabs, which now show 3 letters when collapsed and has a bit of extra space so the longest one does not get cut-off when selected/bolded. Furthermore, the list of plugins is now sorted alphabetically.
Finally, set the plugin listview Dock = Fill (vs. Anchored). This seems to have fixed the listview resize problem I was experiencing.
