Start LT with open file(s) from a file manager

* Couldn't use remote or ipc/callback in cli.cljs because open-file event
  happens before any windows (and cljs) are loaded
* This handles one or more files that are selected and right click opened with
  'Open With' - only verified on a mac
* Preserved behavior that files are only opened in first window
* TODO: open from file manager when LT is already open
Fix open cli path and intro for 2 or more windows

* After first window, cli paths and intro were incorrectly opening and not opening respectively.
* Added a first-window? helper and used it in a number of places. Fixed an incorrect check in
  deploy.cljs