[Pm-utils] [PATCH RFC] Hook isolation, first step towards spinning the hooks off into their own project

[Victor Lowther]

This patch series applies on top of the security fixes patch series.

The goal of this patch series is to make it easier to split the hooks out of
pm-utils at some point in the future, and to make it easier to isolate the
hooks from each other.  To accomplish that goal, this patch does the following:
 
* Stop loading all config files every time functions is sourced.
  This gave every hook and every pm-utils script visibility to all config
  variables, and we needlessly reexported them all everytime functions was
  sourced.
 
  With the changes in this patch, we only source configuration files based
  on the name of the script that is running, and we do not export variables
  set this way.  Settings sourced from the global settings are still 
  globally visible, naturally.
   
* Isolate functionality that only pm-utils scripts should have access to.
  Hooks don't need to know how to run hooks or know the details on how the
  system will suspend.  Instead, they just have access to the functions
  outlined in HOWTO.hooks, and those functions enforce hook isolation.
  
Note that the isolation at this point is neither complete nor perfect --
we still handle all the video options in pm-action.  A mechanism to have the
video hooks directly query HAL for the video quirks would be useful to have.