Editing Administrator list cause error

[LordXaosa]

Hi.
If you will try edit admins list in server config, after adding new item you will get error:
"Constructor on type 'System.String' not found"
Workaround is using StringCollection instead of List...

Fixed with Pull Request: #166

[fvgoulet]

@Commander-Scott , @Moustachauve Is this issue fixed?