Parallel boxes outside inline expressions touch

[sverweij]

a, b;

a alt a: "altbox" {
    a box a : "Do cool stuff",
    b box b: "Do mundane stuff";
};

This causes the mundane box and the alt box to touch borders, though.

(split off from #233)

[sverweij]

With nested inline expressions the issue was even worse, with boxes overlapping the inline expressions ...

• you can check it out on live: https://mscgen.js.org/index.html
• ... or pre-loaded with the chart in the issue

Fixed

Before the fix

(edit 2016-11-16: remove link to feature branch that has been removed from live a while ago)