Proposal: use spaces for grouping

Currently style guide asks people to always put spaces around infix operators.

I suggest to change that, and use spaces for grouping. For example:

```js
// plus has lower priority than multiplication,
// so we're adding spaces to it to show that:
2 + 2*2

// plus has higher priority than ternary operator,
// so we group its arguments together
1+2 ? 3 : 4
```

That's because not everyone remembers operator precedence table, and this way you can avoid using parenthesis while still keeping code readable.