add 4.2 stable drupal folder to d6 repo

4.2.7 updates to drupal folder

increment module versions to 4.2.9
set mysql connection timezone in civicrm.module
For d6 we have no sites using html_purifier module so won't worry about
civi imcompatibility
Revert "Proposed CRM-11966 Html_purifier module incompatibility"

This reverts commit 44061e3870a4ac23d6b6de31430638154c7c2db0.