from 2.2 branch

Made restrictedTraverse public.

Changed logic for restricted traverse (which actually lives in
unrestrictedTraverse) to:

  - Check access for root when absolute path is used.

  - Call getSecurityManager just once.

the "Access Contents Information" permission from being effective in
the root object.

of DateTime object) from 2.2 branch.

Removed registration code for permissions found in classes, since
these are handled by default class init.

registry.

NamedNodeMap).

Verify content type based on image binary representation, not just file extension

signature.  Now it does.