Add empty spec and clean

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (8573507) 100.00% compared to head (15b0eb8) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #36 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 20 20 Lines 849 849 ========================================= Hits 849 849 ``` | [Impacted Files](https://app.codecov.io/gh/Elringus/SpriteDicing/pull/36?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Artyom+Sovetnikov) | Coverage Δ | | |---|---|---| | [...ts/SpriteDicing/Editor/Processors/SpriteBuilder.cs](https://app.codecov.io/gh/Elringus/SpriteDicing/pull/36?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Artyom+Sovetnikov#diff-QXNzZXRzL1Nwcml0ZURpY2luZy9FZGl0b3IvUHJvY2Vzc29ycy9TcHJpdGVCdWlsZGVyLmNz) | `100.00% <100.00%> (ø)` | | | [Assets/Tests/Editor/SpriteBuilderTest.cs](https://app.codecov.io/gh/Elringus/SpriteDicing/pull/36?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Artyom+Sovetnikov#diff-QXNzZXRzL1Rlc3RzL0VkaXRvci9TcHJpdGVCdWlsZGVyVGVzdC5jcw==) | `100.00% <100.00%> (ø)` | |

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