multi-input: handle removal of items.
multi-input: handle addition of element with the pushItem method.
Merge branch '_dev/basic-items-manipulation' into dev
bower: add needed dependencies.
layout: wrap the list with a paper-input-decorator.
js logic: do not bubble down event if a list item is clicked.
style: update style now that the list is wrapped.
Merge branch '_dev/wrap-with-input-decorator' into dev
js logic: add the resize_input function.
style: hide wcalculator.
js logic: resize input on key down.
js logic: resize input when an items_list is mutated.
layout: remove unnecessary code.
Merge branch '_dev/core-input' into dev