bum version to 3.0.8 to show compatibility to openproject v3.0.8
bump version to 4.0.0 to show compatibility to the openproject dev branch
remove todo from gemspec
do not be too strict with our dependencies
update vendored emojify.js
reenable emoticons as upstream bug was fixed

see: https://github.com/hassankhan/emojify.js/pull/35
more beautiful gemspec and a semantic versioning compatible openproject-plugins dependency
Merge branch 'stable'

Conflicts:
	openproject-emoji.gemspec