Enhancement: Convert all layouts to simple layouts

[rsheldiii]

The layout function signature is a little meaty:

module layout(list, profile="dcs", legends=undef, front_legends=undef, row_sculpting_offset=0, row_override=undef, column_sculpt_profile="2hands", column_override=undef)

that's the definition of a code smell if I've ever seen one. In an attempt to localize the logic around layouts i've over-localized, and require all layout logic to flow through the layout function.

simple_layout still contains some magic, but not nearly as much. It sets the length of the key, $row and $column, and the position and expects the child to do the rest. This will make the layout function much more extensible at the cost of a steeper learning curve.