Porting the client part 4: Account and character creation

I redid the missing parts of the login sequence. Account creation and character creation work now. The usability has still some problems though, because the server doesn't report success or failure. That's mostly because the server doesn't even know any failure conditions - it doesn't check anything for plausibility and it is possible to create multiple accounts and characters with the same names. Securing that should be my next priority. And while I am on it I should also prevent accounts from being logged in twice.