Theme: No mini font-size for labels.
Core CSS: Unset browser default min-width for fieldset. Fixes #6077.

The min-width was causing issues in combination with white-space nowrap to get an ellipsis.
Select: Don't set margin-right 0 because a select can be an inline button. Fixes #6103.
Merge branch 'master' into grunticon
Replaced white minus icon.