Added notification center

Added notification center
Added maximum amount, changed style

No longer using bootstrap alerts
Add duration parameter to addNotification (will default to 5s if omitted).
Merge branch 'notifications'
Merge remote-tracking branch 'remotes/origin/achievements'

Conflicts:
	index.html
	js/SpaceClickyGame.js
Merged "notifications" and "achievements" branch
Added toast when achievement is unlocked
Merge remote-tracking branch 'origin/notifications' into notifications

Conflicts:
	js/SpaceClickyGame.Notifications.js
deleted rock
Fixed collisions with duration
Merge remote-tracking branch 'origin/notifications'
Merge branch 'master' of https://github.com/Pchiu/SpaceClickyGame
deleted thumbs.db

a hue
Syncing branch with master
Merge branch 'achievements' of https://github.com/Pchiu/SpaceClickyGame
Spelling, lol