JCNotificationBannerPresenter: remove +enqueueNotificationWithTitle:... - duplicate.
Introduce style parameter to allow using Android Toast style.
JCNotificationBannerCustomView: remove -layoutSubviews - no need to override.
JCNotificationBannerCustomView: rename to JCNotificationBannerViewIOSStyle & move to Library.
JCNotificationBannerPresenter: get rid of delegate.
JCNotificationBannerPresenter: simplify API to match README.
Demo: update style switch for banner/toast.