various improvements
Spider Solitaire HD is a spider solitaire game especially designed for large screen tablets.
It's not designed for phones so it may not work on them properly unless they have very high resolution (more than 480x320 is recommended).
Back button works as undo (notice that you can't undo dealing cards and after completing a color). Clicking on the logo (top right corner) changes background to a darker one.
It was tested on 1280x800 (Motorola Xoom, Acer Iconia A500, Asus Transformer etc.) and 1024x600 (Kindle Fire, Galaxy Tab) screens.
