configurable label sizes in guiclass

[alisterburt]

Hey Talley - great work on guiclass, having a lot of fun with it.

What do you think about the idea of making the label sizes configurable? I find they often take up a bit too much space for my liking and just a little bit smaller would be ideal

Totally understand if this is out of scope for magicgui

[tlambert03]

definitely not out of scope. Falls in the general category of layout improvement which is something that very much needs some love here.