Accounts support

- Add accounts preliminary support - Part Fixes #6 - still requires a lot of game level changes 
  for persistent two player games. 
- Add mute button to mute sound
- Display Online users (currently just an inlined display) - make it more tabular on the right side of the page
- Add notification, user-status dependency 
- Anonymous access can watch games, users need to login to reset the board/undo or place a stone