* Upgrade emoji deps and move to node_modules
Add support for Emoji 3.0 and switch from bower to yarn for managing emoji
dependencies.
// FREEBIE
* Delete old emoji deps
// FREEBIE
* Don't copy emoji on windows
It is no longer necessary since the symlinked image dir is gone.
// FREEBIE
* Update emoji test
// FREEBIE
* Fix emoji tests; remove all overrides of emoji-js functions
FREEBIE
Use emojijs for replacing unicode with image tags for display. We were
already using it to replace colons with unicode. Additionally it has
a companion data repo that is kept up to date with images from all
the common image sets.
// FREEBIE
