badly designed `Select` component

[remicousin]

          That's a badly designed `Select` component. I think it should work like this:

def Select(id, options, labels=None, init=None):
    ...
    init: one of the options in `options`, to be used as the initial value. If not specified, the initial value will be the first option.

Originally posted by @aaron-kaplan in #481 (comment)