New boards and pieces, impasse!

Hey everyone!

We added some new boards and pieces, thanks to CouchTomato87 and Kleffa. Also some new sounds were added, courtesy of ddugovic and CouchTomato87, try them out and let us know what you think.

Another big change was changing the impasse rule. You can no longer offer a draw and try rule was added - meaning you can force a win, if both kings reach opponent's territory and your king gets into your opponents king's starting square. In the future 24 points rule is going to be implemented.

Discord server was created, come and say hi! https://discord.gg/YFtpMGg3rR

This site is still in it's early beta stages, if you find a bug you can report it here https://github.com/WandererXII/lishogi/issues. I ask for some patience, I try to fix stuff as fast as I can.

Thanks for your support everyone!