Bugs in filter administration and tableDrag

Since I don't know whether #558666: UX/security: Revamp text format/filter configuration will make it in (though I seriously hope so), I extracted a couple of unrelated bugfixes of that patch.

Summary of the changes:

• Various missing variable declarations in tabledrag.js.
• A better tableDrag.restripeTable() method, which accounts for hidden table rows and uses a much more simple logic.
• Simplifies the user role access selection and also removes the unnecessary fieldset around those checkboxes.
• Ensures that a hook_form_alter() implementation has access to the text format and stored filter configuration in the text format edit form.
• Ensures that a text format name is saved without leading and trailing spaces.
• Ensures that internal Form API values are removed from the submitted form values before a text format is saved.
• Fixes a wrong function argument order for filter settings callback functions, so all Filter API callbacks use the same arguments.

Additionally, these changes also make sure that I'll be able to implement the new text format and filter administration interface in a contrib module, if it turns out that I will have to.