The username regex validator can be changed in platform_options.yml.
Merge branch 'master' of https://github.com/claroline/CoreBundle into userrname-authorized-chars

Conflicts:
	Entity/User.php
	Library/Configuration/PlatformConfiguration.php
	Library/Configuration/PlatformConfigurationHandler.php
Adding missing coma
Merge pull request #717 from ngodfraind/userrname-authorized-chars

Userrname authorized chars