Update eventmachine to 1.0.4.

This will allow the gem to be installed on Ruby 2.2.
FIX: only create animated thumbnails for GIFs
new vBulletin importer (uses mysql dump instead of multiple csv files)
Run after_fork hooks correctly on Phusion Passenger
Merge pull request #3054 from phusion/master

Run after_fork hooks correctly on Phusion Passenger
Merge pull request #3053 from tgxworld/update_event_machine

Update eventmachine to 1.0.4.
Second try at making heart pulse. Go faster, stay coloured.
FEATURE: custom emojis
FIX: use cache to store custom emoji
FIX: custom emoji weren't properly baking
FEATURE: remove override stylesheet option, too confusing
FIX: stable ordering for site customisations
FEATURE: more than 1 site customization can be enabled at once
FIX: more robust site customizations

Rewrote site customization to use distributed cache and a much cleaner
css delivery mechanism
correct live reload code
FIX: no way to remove site text