Lobby, Add Bots button

fixed spacing 1

Challenge button renamed to Add Bots, no longer assigns a team. Enabled button for ra, cnc and d2k

Added One vs Me to Assign Teams, button hidden if not admin

formatting, fixes

formatting, fixes

more fixes
Merge branch 'bleed' of https://github.com/aperkins81/OpenRA into bleed
rebase
bot is only added if slot is empty or contains a bot