First work on login and user management
Login and logout working for the first time
User factory method for creating SocketConnection object for Tornadio2
"Writing" backend methods now protected (need logged in user (or dummy user if access control is disabled) to perform action), most "writing" frontend controls disabled if no logged in (or dummy) user returned from backend.
Added roles (user and admin) and according requirements
Furhter work on user management
Fixed settings for gcode file list
User management now working

Also reorganized javascripts a bit (as preparation for some refactoring coming up) and renamed templates from ".html" to ".jinja2".
Fixed some merge bugs