This patch adds a default zoom level for pannel views, eg. t-n/-key pannel and buttons window. Only newly created views will get this zoom level, existen views are not altered since this would destroy setups like a extra big material preview pannel for example.
A defaul zoomlevel can be set in the user prefs under Styles>Style>Pannel Zoom Level. It ranges from 0.5 - 2.0 like v2d.max-min/zoom.
Testing showed that a value of 1.45 gives nice slender buttons, which reveal almost twice as much interface as the default sized ones, but still doesn't nudge down the font size.