Updated test.rb
+ Names of failed tests in the final reporting are displayed
Update *Infos.rb, database.rb

*Infos#id => returns the id of the record
UserInfos.{groups,files} is now a hash[name => {Group,File}Infos]
UserInfos#{add,del}{Group,File} and tests
FileInfos#addFile : 'rights' parameter has a default value of 0640