Add permission to administer block classes

Currently the module doesn't check for permission in hook_form_alter(), it does only in the submit callback, that is IMO a bad practice: if the user doesn't have the permission to administer blocks or block classes, she should not see this option at all.

This module shouldn't check for the "administer blocks" permission in hook_form_alter() because the user can't access the blocks configuration interface at all without "administer blocks" permission. It's a moot point.

I'm not entirely convinced we need a separate permission to add block classes. It seems to me that if a user can be trusted to move blocks around the page, alter their content, and change its visibility -- especially using PHP -- they can certainly be trusted to add something as benign as CSS classes. We need a clear use case for a granular permission before we can introduce one.

It's also worth noting that adding a new permission to Block Class will cause problem for users upgrading to the new release. They'll need to know to enable the permission on their site; otherwise, that form element will not appear, and the module will appear to be broken. Most users do not read release notes, so they probably won't know about this change. The benefit of adding a new permission will need to outweigh this confusion (and the resulting posts to the issue queue about how the the form element suddenly "disappeared).

Can you provide a clear use case for a user who can be trusted to fully administer blocks but not add CSS classes to them?

Patch committed.

You're right. Tried to amend commit, merge tree looks really weird now.

Committed.