added tests for html value_is_current() method
added tests for html smart_close() method
added html method debug_mode() to toggle debugging on/off
added tests for html debug_mode() method
use internal debugging toggle for html helper instead of WP_DEBUG
added test for html open() method with debug mode enabled
improved test coverage of html close() method
added test for html unsupported auto close tag type
added code coverage whitelist to phpunit config
the html testSmartCloseEmpty test no longer outputs data
dont check files_loaded class property as it fluctuates too much during development