autoset width and height

[DenOfEquity]

• When loading into img2img, added an option to automatically set Width and Height from image (Settings -> img2img ->After loading into Img2img, automatically update Width and Height).
• fixed Resize by Scale display, now correctly rounded to multiple of 8
• That display now updates on change, instead of on release, so it updates as the slider is dragged and when an image is loaded (if option enabled)
• Also fixed new width/height calculation inside img2img function, same fix, (affects infotext)