Makes all canvases obey the same rendering parameter. Also keeps the
canvas selection with the anti-alias selection, which makes logical
sense. Reduce the antialias selection to a single choice rather than
two different choices for different canvases
Sometimes the grid thickness setting does not work, depending on some locale setting.
Core developers are not able to reproduce this issue related to a double conversion.
So these wxSpinCtrlDouble are replaced by a wxSpinCtrl (using ints) and a wxChoice.
