Added configuring of behaviors to the editor config.
Propagated new editor i18n tags.
Added random session pair choosing

Due to a bug I cannot test this immediately
Put back the sort for the leaderboard handler.
Made editing thangs in the level editor not so slow by avoiding calling level.serialize.
Merge branch 'master' of https://github.com/codecombat/codecombat
Fixed random sessions fetching
Removed defaults on schema for ladder-related things
Hotfix for #550
Another hot fix for #550
Fixed bug in next game button, fixed wizard positions
Working on new loading view design.
Fixed two bugs with destroying sprites.
More work on the loading view.
Merge branch 'loading-view'
Oops, don't keep sending ladder updates just to me.