fix: username has to consist of url safe characters
fix: username has to consist of url safe characters

MatthiasApsel/cforum,CountOrlok/cforum,ckruse/cforum,CountOrlok/cforum,CountOrlok/cforum,ckruse/cforum,MatthiasApsel/cforum,ckruse/cforum,MatthiasApsel/cforum,CountOrlok/cforum,ckruse/cforum,MatthiasApsel/cforum