Fix StringInput examples.

Somehow got mixed up with Popover ones.
Fix consistency with class naming
Close #36: add StringInput-multiline variant class
Close #37: wrap label text separately.
Close #26: Add -bare variant of Buttons.

This removes the background, leaving just the text or the icon.
Fix StringInput demos (again)

Missing patching that lets it set the output value.
Fix #40: disable the disabled StringInput.

The disabling needs to happen after every render, not just on initialize.