events/server: add ServerEvent
plugins/hang: send ServerEvents
player counts are integers
proccess: send ServerEvents
add plugins/push.

sends push notifications to various APIs, e.g. NotifyMyAndroid:
http://i.imgur.com/YXsUXMI.png

supported endpoints:
 - SMTP (otherwise known as email)
 - NotifyMyAndroid (https://www.notifymyandroid.com/)
 - Pushover (https://pushover.net/)
 - Prowl (http://www.prowlapp.com/)
update mark2.default.properties for 78f84b5