AUI-1710 LayoutBuilder should guarantee rows will have size 12
AUI-1676 Move drag handle throughout the row
AUI-1702 LayoutBuilder should receive array of breakpoints
AUI-1703 New Layouts should enforce row sizes to equal 12
AUI-1705 Buttons to add and remove columns
AUI-1705 Source formatting
AUI-1702 Fixing behavior on IE8

IE8 doesn't have the `indexOf` function for arrays, so we need to use Y.Array.indexOf instead.

IE8 also can't understand rgba, so changed the demo to use regular colors instead.