Enhance beans_get_layout_class to build multiple layouts

[hellofromtonya]

The beans_get_layout_class() is very powerful in that it automatically builds the class attributes for the content and each of the select sidebars based upon:

1. The selected layout for that web page.
2. Each enabled sidebar (widget area).

However, it's limited to one set of grid configuration settings:

	$args = apply_filters( 'beans_layout_grid_settings', array(
		'grid'              => 4,
		'sidebar_primary'   => 1,
		'sidebar_secondary' => 1,
		'breakpoint'        => 'medium',
	) );

Let's enhance this function, allowing you to configure multiple breakpoints.

For example, let's say you are building a theme that uses large and medium breakpoints. This enhancement would allow you to define and configure what you want and then Beans just handles it for you.

Notes

The problem was original identified by Alex in this Community Forum post.