BW::UIAlertView with a text field, password field, or both

make_ui_alert_view_with_text_input

https://github.com/rubymotion/BubbleWrap

``` ruby
#options
opts = {
  title:"A question",
  message:"A description.",
  buttons:["Cancel","Okay!"],
  cancel_button_index:0
}

#make an alert view with one plain text field
alert = BW::UIAlertView.plain_text_input(opts).on_click do |al|
	user_typed_this_text = al.plain_text_field.text
	if al.clicked_button.index==0
		#clicked the Cancel button
	else
		#clicked the Okay! button
	end
end

# show it
alert.show
```