Implemented additional information parsing for users other than the logged-in one
Added Posts and PostsPerDay properties in user class. The update method now also updates both properties
User note parsing and visitor message statistics parsing
Refactored parsing of user statistics. Thanks and visitor messages are now also parsed properly
Users are now shown as invisible if the last_online element couldn't be found
Splitted the User.Update function into small subfunctions, renamed Usergroup -> Rank
Merge pull request #6 from Mostey/user_remastering

Refactoring of the User class, extensions to the Update function