if action buttons are shown (either the nothing selected actions or the
stuff selected actions), when a checkbox is selected or deselected,
count how many checkboxes are selected. If it's zero, then show the
new template/folder buttons, if it's non-zero, then show the move
options.
Under the hood, we set the `currentState` variable, then the render fn
shows that element and hides all others.
have a bunch of separate elements within the sticky_template_forms div
that we hide or show based on button presses and such. This commit just
sets up the class - it doesn't actually deal with button presses or
checkboxes etc yet.