Large font sizes for infobox don't render correctly

[azonenberg]

Looks like spacing of decodes and overall WaveformArea height doesn't take the infobox height into account. If the font is too large this can cause infoboxes to overlap or become unreadable.

Especially a problem on high DPI (4K 15") displays.

[azonenberg]

Wontfix in glscopeclient, ngscopeclient's UI should all be scalable.