FEATURE: log out user everywhere and refresh/redirect

also see -- https://github.com/discourse/discourse_api/pull/47

cc @SamSaffron 

Edit: 
WIP
 Done!
this is not enough, which is why this gets tricky, if you are viewing a private topic for example it may be an issue.

ultimately I think its up to logout api, some people will want it to send users back to the home page unconditionally, some will be happy with "refresh" 

so default is simply to refresh the page, but optionally you can tell the logout api where you want to take the user on logout.