Make RAYGUI_WINDOWBOX_STATUSBAR_HEIGHT customizable at runtime

[jmrico01]

I was creating a GuiPanel with a default font size of >24, and I noticed that everything scaled nicely except the panel header, where the text is overly crammed. I poked around the implementation and noticed that this is controlled by #define RAYGUI_WINDOWBOX_STATUSBAR_HEIGHT, which is only customizable at build time (also used in GuiWindowBox, GuiScrollPanel, etc). I'm currently scaling the default font size based on the window resolution, so it would be nice to modify this status bar height at runtime.

You can see the text Menu appears very crammed here:

Maybe this could be made into a raygui style setting, accessible via GuiGetStyle/GuiSetStyle?

[raysan5]

@jmrico01 there are actually several defined values that should be reviewed and probably exposed as style options...