add target(fn) for defining separate target el from clicked target

test using target(), clean up test/index
add model.dump, model.load for serializing model data

add selectAll, deselectAll; run deselectAll before reset

add test example using localStorage to persist state across page refresh.
it's ugly but it works. I think the next step is to move some of that
within the togglecollection, e.g. toggles.store(myStore)
add store() for saving model state (to localStorage, etc).
note: assumes store has marcuswestin/store.js interface.

change model.dump() to model.toJSON()
fix edge case ( model.refresh() when model.el not set )
rename select(), deselect(), selectAll(), deselectAll() -> toggle*
to avoid name conflict with enumerable select()

add ids(), selectedIds(state) convenience methods for returning array
of clicked toggle ids and array of toggle ids in state, respectively

add test of this in test/index.html
version bump