Create Permission to use AJAX plugin

Create a permission like "use ajax forms" that enables / disables the module's functionality per role. A few reasons for this:

1. You don't want anonymous users to use the ajax module or some other role
2. You want the User Experience to meet a certain workflow that doesn't have the AJAX functionalty
3. I've found several times now where I want it for the admin but not for the end users who are used to the system behaving a certain way
4. Other modules that leverage the ajax functionality yet don't want users to have access to it outside of that environment (where certain roles have access to that interface)

I see this as being critical as I've started to find groups of users who have problems with the AJAX module because they don't meet browser requirements (or at least when used in conjunction with TinyMCE module). This would be a pretty simple "fix" I think, just wondering if it's something the project would be interested in before I go and hack my own version to add this in.