simple policy for file I/O functions

 File::Policy defines the policy for file I/O with modules such as
 File::Slurp::WithinPolicy. The purpose is to allow systems administrators to
 define locations and restrictions for applications' file I/O and give app
 developers a policy to follow. Note that the module doesn't ENFORCE the policy
 - application developers can choose to ignore it (and systems administrators
 can choose not to install their applications if they do!).
 .
 You may control which policy gets applied by creating a File::Policy::Config
 module with an IMPLEMENTATION constant. You may write your own policy as a
 module within the File::Policy:: namespace.
 .
 By default (if no File::Policy::Config is present), the File::Policy::Default
 policy gets applied which doesn't impose any restrictions and provides
 reasonable default locations for temporary and log files.
 .
 The motivation behind this module was a standard, flexible approach to allow
 a site wide file policy to be defined. This will be most useful in large
 environments where a few sysadmins are responsible for code written by many
 other people. Simply ensuring that submitted code calls check_safe() ensures
 file access is sane, reducing the amount of effort required to do a security
 audit.