Coloring and formatting

This PR contains some changes to make coloring and formatting configurable. I removed your formatter because it was appearing on the "General" section instead of on its own.

There is also a brace matcher now, it makes a world of difference when creating a brace and pressing enter, you actually get the brace in the right position now.

I also changed the grammar a bit so the match block gets correctly indented.

The problem is, the preview on the configuration page for indentation doesn't really work, i.e. there is no indentation whatsoever for some reason.

Also, I'm not sure if it's because of my changes (I'm suspecting it has to do with the brace formatter) or it was like that before, but the following:

```rust
fn main() {
    method();
    if true {
        method();
    }
}
```
...is indented as
```rust
fn main() {
        method();
        if true {
            method();
        }
}
```
(so doble the indentation in the first block, inner blocks are ok)

If you have any ideas, maybe this can be fixed before merging. I'll check the brace formatter as soon as I can.