MarbleBattle: phone and network tests

Test pages for spikes S-05 and S-06. They send timing and sensor-rate numbers (no personal data) to the project server so results can be read.

1. Tilt, installed app, guest id (S-05) 2. Connection latency (S-06)

Steps for S-05: open this page in Safari, run test 1 once. Then Share, Add to Home Screen, open the new icon, and run test 1 again. The two guest ids and the display mode are logged.