Config variables are not applied to TinyMCE configuration

HTML/QuickForm/tinymce.php implements a function SetConfig() to set config variables for TinyMCE.
Unfortunately these variables are never applied to the configuration.
The attached patch file fixes this problem.
I wrote a drupal module to integrate IMCE with TinyMCE (and CKeditor), but without the ability to set config variables for TinyMCE it would not work.
This patch makes it also easy to write a drupal module to customize TinyMCE for some or all forms. Like setting absolute urls for some forms (e.g. Newsletters, Mailings,...) and leave them relative for others.