Prevent page reload when choosing a color created by the user

1. Create colors with the color picker
2. Click on a newly created color
3. Oh noes it reloaded the page and my design is gone :cry: 

This fixes it. The diff looks huge but it's because of a bunch of whitespace. There is [no big changes](https://github.com/romainberger/voxel-painter/commit/6602e334728f09e1a15411f8933e95b05479b0ea?w=1) actually.