#224, #225, and a misc. tweak or two

[abalabahaha]

• Every second, each player loses a percentage mass. The percentage is calculated as the mass loss ratio in the config divided by 1000 (Losing Mass Cell per second as feature #224)
• Introduces a upper food limit, which limits the food rather than the mass. The global mass limit is still in place (Modify quantity of food spawn #225)
• Server sends integer mass
• It now balances mass when players aren't on, since the board would be devoid of/filled with too much food if nobody was playing before somebody logged on