display current turn color
display move history
css/html preparations
added nice github button
fixed bug on castling
added test url
preparations for #10

- refactored fieldIsCoveredByColor: added field parameter
- refactored playerIsInCheck: added field parameter
- added function for create field copies
implements #10
implemented #12: rotate the game for the black player
removed debug output
finished list of killed figures (#9)
Merge branch 'feature/lost-figures'

Conflicts:
	peerchess.css
Merge pull request #13 from MatthiasLohr/feature/move-in-check-detection

implements #10
fixed spelling
added Lukas Barz to contributor list
HTML5 compilant code
added license information for beholder.png
castling logic rewrite as preparation for #15
should fix 1, 2 and 4 of #15
fixed #15