Deleted an old backend template
No need to import classes if we can use them statically
Mail templates have been dropped in 2.0
Removed check for extremly old Isotope version
Prevent data loss when old Isotope is installed
Allow to pass a CSS class to backend overview modules
Disable unavailable reports

We don't need to remove them. Only admin can see them and control access
through group settings.
Added compressed version of reports css
If backend permission for group is empty, all groups are allowed
Moved product permission check to helper method
Check permissions on shop config when generating available currencies