Changing text spacing properties
I'm trying to change the line spacing on some API generated text. There doesn't seem to be a way to do it with current JS API, but is there a way to add it using the old API?

`var text = group.newText({alignment: NSTextAlignmentCenter, text:copy, fixedWidth: true, font: NSFont.fontWithName_size_("Gotham HTF Book", 68.5)})`

After looking at the code for the [Sketch Set Line Height plugin](https://github.com/getflourish/Sketch-Set-Line-Height-Plugin/blob/master/Sketch-Set-Line-Height.sketchplugin/Contents/Sketch/script.js), I tried using `text.lineHeight()` and `text.setLineHeight()` to no success. They come back saying those functions do not exist.

Any ideas? If there's a way to do it we can see about adding it to the JS API