Added slack to DI config
Added support for Slack to XSD
Updated position of icon_emoji variable to prevent BC breaks with monolog/monolog see https://github.com/fotomerchant/monolog/commit/ff6c458260440f1a259c94950222a42209e1b51c
Moved icon_emoji parameter to correct position for SlackHandler
Merge remote-tracking branch 'fotomerchant/feature/slackConfig'

Conflicts:
	Resources/config/schema/monolog-1.0.xsd