NanoUI fixes

- Fixes #6013
- Reverts temporary fix that removed the problem formatting (#6343)
- Renames red and yellow button classes to be more self explanatory
It would be something like this I think:
```
.button {
    /* button stuff*/
}

.button.red {
    background: #cacc00;
}
```

But in order to use the red button you would have to use something like ```class="button red"``` which would require changing all of the nanoUI templates.