maple classic™ 
custom emojis notes:
- custom emojis show nominally at 18x18px in timelines but 16x16px on the control panel. make em for 18x18px so they don't get blurry in usage
- custom emojis do not refederate. if you get it wrong once, use another shorthand or the fixed version will not show on remote instances.
@squirrel I'm thinking when I eventually upgrade to 2.0 I'm going to make a "refresh federated emoji" task and put it on a weekly cron