Allow user to disable manifest and offlineMode (#14213, #14197)

User can disable them using  @OfflineModeEnabled and @CacheManifestEnabled
annotations in Servlets or in UI classes.

Change-Id: Ia0f3ee33080dcf59b4de166a7d8bb5d6cc6a7c3d
Document NavigationButton gotcha when not target specified (#13028)

NavigationButton automatically navigates to a placeholder view on the client - even if no target is specified - so if the click listener does not change view, the user is stuck on an empty view.

Change-Id: I444e3143bf9f89da973a311b7e29672cb4e8b90e
Always animate on navigateTo(), don't 'overnavigate' (#13989 #14210)

A server-side navigateTo(target) will now cause an animation even if the target is not nextView.
Also fixes a situation when server-side navigateTo(target) in a NavigationButton caused double-navigation to an invalid state if the target happened to be the nextView.

Change-Id: Ie12a983f71bdd31a7403801a1834e6385b10b671