Refactor State Architecture

[pik]

There are several objectives that should be achieved or more easily achievable with a refactor.

**Separate state (as much as possible from Polymer components) **

Polymer state changes and notifications are some of the worst I've used and constantly require un-pleasant work arounds, more so computing things that could be computed outside of the Poylmer Elements: such as the filtered list of comments based on user-settings (by passing UI changes of user-settings to a backing comment-tree) would also make it easier to potentially switch to a different framework (React) at some point in the future.

**Delay tree updates (especially on first load) to improve performance **

Debounce certain outgoing network effects (such as flags, to allow toggling without outgoing events)

This (debouncing) is currently done for e.g. persisting custom user settings but should be more wide-spread.