optional classes param to list classes

untested code, sorry
fixed list-classes match
pass nil as count instead of array length
made sure classes was always an array

had to convert the setting into an array instead of a hash so classes is
always an array
fixed list_classes bugs and bad match
being noticed for admin only when not necessary
Merge pull request #5 from Faek/master

list-classes accepts class parameters for non admin users final hopefully