Refactored ic_picture_shade_bottom.*.png to ic_picture_shadow_bottom.*.png

Refactored ic_picture_shade_bottom.*.png to
ic_picture_shadow_bottom.*.png
Refactored ic_picture_shade_top*.png to ic_picture_shadow_top*png

Refactored ic_picture_shade_top*.png to ic_picture_shadow_top*png
Merge branch 'master' of https://github.com/taghere/gui