Using include_once instead of include so external calls to beautify functions dont result in duplicate include.

#358847 by Garrett Albright: Refactored beautify_htmltidy_test to fix open_basedir restriction errors.

Stop processing output for authenticated users until we figure out a work around to the problems on node/add.

Initial commit of Beautify module. This module buffers the HTML output of Drupal and processes it through HTMLTidy, htmLawed or a set of built-in functions for beautifying (auto-indentation), flattening (removing indentations) and compacting the source code output to the browser.