Merge branch 'login' into iss24
fixed accidentially merge-conflict
removed merge conflict, added password-handling w SHA2-hashing
added configuration-attribute for hash-rounds
added session-handling
switched to ruby-privacy for method
added configuration-attribute for session-timeout
added controller for session-management
corrected config-variable-name
removed session-controller
added before-filters for session-management
changed redirect-directive
tried to fix semantic-ui-error
fixed spelling
fixed load-chain for gems
several bugfixes (spelling & encoding)
added session_migrations again, in order to fix `Could not find table 'sessions'
added and activated login-mechanism
fixed rake-task accounts:create_admin
added support for test-environment, fixed model-attribute-access