add support to less functions paramters braces

this PR adds better support for less functions braces (no new lines between function parameters)
e.g: the new code outputs this
```less
.box-shadow(@shadow: 0 1px 3px rgba(0, 0, 0, .25)) {
    -webkit-box-shadow: @shadow;
    -moz-box-shadow: @shadow;
    box-shadow: @shadow;
}
```
and the old code outputs this:
```less
.box-shadow(@shadow: 0 1px 3px rgba(0,
0,
0,
.25)) {
    -webkit-box-shadow: @shadow;
    -moz-box-shadow: @shadow;
    box-shadow: @shadow;
}

```