Add note about stb to 3rd party credits in LICENSE and docs
Update things to point to the new builds page available
Install UI.pdb to get better callstacks (zip distributes all pdbs)
Make installer add thumbnail & file ext registry entries by default

* This might be the wrong thing to do, I've changed my mind on this a dozen
  times. I think most people will want these, and I don't think it's a bad
  thing to include it as the default setting - people can still go to
  customise and unselect it. I thought most people would do custom and then
  opt-in since most will want it, but I suspect (from watching people run
  the installer) that most people hit typical, and so don't get these.