Spacing between graphics in sprites

Original Patrik's description

It need to be possible to add spacing between the graphics in sprites. This is so that sprites can be used as background images in elements highter than or wider than the individual graphics.

Brief analysis

There seems to be a general pattern emerging from this task: multi-level defaults for certain properties of sprites and individual images. More description below. The three levels on which the properties can be defined are:

1. Global level, applies to all sprite images and their individual images
2. Sprite image level, applies to all individual images in the sprite
3. Individual image level, applies to the individual image only

Higher level values can be overridden on lower levels. Properties affected could include:

• sprite-margin-*

TODO: complete specification of this ticket, change the titile.