Tweak atmos UI slightly

 * handle case of signed in, but not running by letting you toggle
   whether we'll use atmos when we do run
 * rename the observables that control the atmos status UI
   so it's clearer they cover all cases and are exclusive
 * de-hyphenate sign-in
 * split doRestart from the button click handler
Merge pull request #23 from typesafehub/wip/havocp-atmos-ui

Tweak atmos UI slightly