refactor(kff.View): minor performance optimizations
refactor(kff.base): minor performance optimizations
refactor(kff.FrontController): decouple hashchange observer from FrontController and provide separate service for state manipulation instead.

A new service HashStateHandler provides legacy hashchange event manipulation/listening. I can be easily replaced by HTML5 pushState API wrapper service or another state handler (i. e. state handler that works completely without url).