- add functions to recursively dump hashes and arrays into a string
  suitable for printing as debugging output (great for data structures)

- add three new trigger strings

- add 'use strict', do corresponding cleanup

stated changes:

- move special-cased stuff in handleEvent for PXEBOOTING and BOOTING into
  triggers (PXEBOOTING, BOOTING, and CHECKGENISUP)

- clarify (via comments) the existing kinds of triggers and which ones run
  when, and add a new kind (global "any-mode" triggers). We already had
  per-node mode-specific, per-node any-mode, and global mode-specific
  triggers. Now you can have a trigger that is good for any mode in a
  given state, that can be overridden on a mode-specific basis. This is
  great for PXEBOOTING, BOOTING, and ISUP, since they each have a trigger
  list that should be run regardless of what mode you're in. Now they only
  require 3 entries instead of 3*N that have to be maintained per mode.

     # A note about triggers:
     #
     # "per-node" trigge...