Highlight inputs/outputs with bad connections.
Update connections in more cases when input/output scene bounds change.
NodeConnectionsList redisplays when inputs/outputs change.
NodeConnectionsItem no longer recreates all connection items after changes.

After various changes such as adding inputs/outputs, all the NodeConnectionItems
would be recreated.  Now connection items persist for the life of the connection.
Work around Qt bug where a QGraphicsItem's childBoundingRect was updated.
Reset the label of an unknown input/output/variable to the name.
Save/restore main-window geometry and open files with QSettings.
Added LuaDocument, editing .lua files, saving/restoring EditMode settings.
Changed title of ScriptSceneDialog.

This only shows inputs and outputs; rename class + file?