fix: completion-fn called twice in will-enter on initial page load

[yenda]

At least on Chrome, the browser sends an initial pop state event that has no state, and does not correspond to the expected forward or backward distinction handled by the pop-state-listener. As a result, installing the htlm5-history triggers a routing event, that is then immediatly followed by another when one restores the history, which is the common use case in RAD.

[yenda]

I also included a patch that I have been running in prod for a while that fixes another history related issue, where forms would not properly navigate after navigation has been initially interrupted because of unsaved changes