Fix corrupted icons after Spacegray theme update

[RealJTG]

This fixes icon problems after Spacegray theme update (#206)

@marcofugaro have changed paths a bit here https://github.com/kkga/spacegray/commit/a3cf933585ac8fbb67e02c350d9ee614642c17af

Before:

"layer0.texture": "Theme - Spacegray/Spacegray/close.png",

After:

"layer0.texture": "Theme - Spacegray/assets/close.png",

[drewcassidy]

the icons in the sidebar are still broken

[robertwt7]

Yeah i'm still having this issue as well, any clue why?

Thanks