Cover mode improvements

[andreyvin]

I would like to have cover mode for horizontal photos and contain for vertical.

I have monitor 16x9. My photos are 3x2 or 4x3 or 16x9. For vertical photos cover mode remove lot of details, but it is good for horizontal.

I make simple change in Monitor.readMetadataImage to be as expected for me: if (width < height) this.imageSettings["fitTo"] = "contain"; else this.imageSettings["fitTo"] = this.screensaver.config.getPersistantString("fitTo");