player registration
allow get/send notifications to players
Merge branch 'feature/register_players' into develop
BUGFIX solved error with config paths
allow cross-domain requests
using events to async notify
added some comments to the engine
only allow POST for request changing server data
removed unused lib
enable jsonp
REFACTOR code style
GameRunner send events
changed '/games' prefix to '/engines' for list, info and create engine
created a dummy GameRunner events listener
raise events from handler to process
game_listener listen for process events
using PlayerStore to save/read  notifications
require authentication header to send some commands