Move variables from the grids module into a variables partial.
Move variables from the flow module into the variables partial.
Move variables from the background module into the variables partial.
Add $zen-auto-include-box-sizing variable.
Move raw image data URIs from the background module into a variables-background partial.
Optimization: Prevent duplicate padding declarations when using zen-grid-flow-item().
Move global variables into their own partial.
Add @see docs for the background variables.
Change doc references of "zen" to "zen grids".