whitelist, not blacklist!

This fixes an issue where things like local variables
were being interpreted as method names.

Example:

before_filter :blah, filter_options

"filter_options" was being treated as if it were a method name,
which was wrong.

[ci skip]

which does not appear to be in Rails 3

same effect, less code

attr_accessible is inheritable, don't warn if a parent is protected