Demotes EXTChartView.grid to a read-only, non-IBOutlet property, and automatically synthesises it.
Aligns the initial art board frame to the grid.
Smaller default art board size.
Removes EXTChartView.gridSpacing since this value is kept by EXTGrid.gridSpacing, adds a context pointer to the KVO observation of EXTGridAnyKey, fixes a bug where moving the art board could make it not aligned to the grid.