After populating the list of plugins, auto-size the columns once. In the Resize event handler, do what you did before but account for the scrollbar width too. Prevents horizontal scrollbar appearing except for really fast resize movements.
I didn't try it yet with fewer than a scrollable # of plugins yet.
This cleans up my commented out code from #128.
Polishing a few rough edges:
* Enable scrolling on the Plugin List view. It only fit 6 or 7. I have 13.
* I fiddled a bit with column auto-sizing (left it commented out, see comment).
* A whole bunch of tweaks to the settings view:
* first row of controls was cut off at the top (under the window title bar)
* fixing that revealed uneven spacing between columns
* action buttons were teensy tiny and unreadable
* settings view columns were too narrow (200 px).
* added some spacing to help with readability
* settings windows now start in center of current screen rather than some random place.
