Adds two new theme vars:
- menu.width.min (menu will never be smaller than this)
- menu.width.max (menu will never be wider than this + padding)
A fixed menu width can be achieved by setting
menu.width.min == menu.width.max.
Add theme options:
- menu.separator.width
- menu.separator.padding.width
- menu.separator.padding.height
- menu.separator.color
Support separator lines defined by <separator />
Note that separator labels (with text) defined by <separator label="" />
are not supported.
Move font_texture_create() to font.c so it can be used for purposes other
than rendering the menu, for example server side decoration.
Refactor menu.c and menu.h to use this more generic font_texture_create()