Set proper copyright on tor-check

tor-check has a license file (MIT) which is good but that file lacks copyright information so far. I think we should put the tool under Tor Project copyright but we will need to ask folks who had contributed whether that's okay. There have been quite some folks contributing over time, so this might not be trivial to solve. :/

• Adam McCarthy
• Amogh Pradeep
• Arlo Breault
• championquizzer
• emmapeel
• Gaba
• Georg Koppen
• Hiro
• Iain R. Learmonth
• Kevin Butler
• kezzle
• Matthew Finkel
• Matt Pagan
• Paul Walker