Optimize SVGs

`logo.svg`: 

* __Original__: 570 bytes 
* __Optimized__: 244 bytes  
* __Reduction__: 326 bytes [57.19%]

`navigation.svg`:

* __Original__: 561 bytes 
* __Optimized__: 228 bytes  
* __Reduction__: 333 bytes [59.36%]