Fixed some Log:: messages that used incorrect syntax and did not print
some variables. Made all log:: messages use the same components 'addons'.
Merge branch 'master' of github.com:supertuxkart/stk-code
Fixed error message to correctly say that online user names needs to
be at least 3 characters long - though at this stage we need to
wait for the server to be updated as well, since it will now reject
a shorter user name.