Blender Git Loki

UI: Expand Enum Items Over Multiple Rows

Expanding enum items in a small area would render the names with
dots, what is a bad solution. When you use expand directly on a
`grid_flow` or `column_flow`, it will render the items on multiple
lines, giving more control to the developer.

Reviewers: campbellbarton, brecht, mont29

Differential Revision: https://developer.blender.org/D4698