Work items drawer history does not work as expected

Reported problems

1. When the drawer is open, then a new item is opened, "Back" changes the URL to the prior item but does not actually show the prior item
   1. There's a bug in the history mechanism after switching between different issues in the drawer. Going back to an URI with NO show parameter correctly hides the side panel again, but switching between two URIs that DO have a show parameter keeps showing the wrong (last shown) issue.
2. History not set if item not fully loaded (broken out into #534727)
   1. Yet another history bug where navigation by forward/back doesn't work reliably if the asynchronous parts haven't fully loaded yet. Sometimes 2 back-actions are required to reverse only one click, and sometimes the the changed URI wasn't pushed into the history at all so the back-action take you out of the issues list.