Web socket for display control

[jpschewe]

• [x] Push url to display rather than push and poll.
• [x] Regularly send name to keep times up to date.
• [x] Make remote control update from socket? -> not at this time
• [x] send UUID parameter to all display pages
• [x] support UUID parameter on scoreboard
• [x] support UUID parameter on playoffs
• [x] support UUID parameter on slideshow
• [x] push url change when the remote control page updates
• [x] test playoffs page load
• [x] test playoffs select brackets, both default and other display
• [x] Test scoreboard load and setting of award groups
• [x] test slideshow selection
• [x] Test finalist teams display
• [x] Changing default display needs to update any display following the default display
• [x] test admin brackets, need to fix UUID issue for the DisplayInfo object
• [x] test printable brackets

[jpschewe]

Maybe use server-sent events instead of websocket? Although note that only 6 pages can simultaneously be using server-sent events unless we are using http2.

[jpschewe]

Stick to websockets so that the display name can be sent.

See if I can remove the need for session variables.

Use a form parameter to track the display name from page to page. Use JavaScript to handle the name parameter.

Don't specify name on scoreboard custom pages, don't want these to show up as displays.