Perform the full bootstrap.
GOAL: All the standard services (database, DAOs, translations, settings, etc) should be loaded.
MECHANICS: This basically calls CRM_Core_Config::singleton(TRUE,TRUE).
NOTE: This is technically a reboot. Preboot started things off, but it
booted with CRM_Core_Config::singleton($loadFromDB==FALSE). Now, the DB is
populated, so we can teardown the preboot stuff and start again with $loadFromDB==TRUE.