Give preference to an XML_EDITOR or EDITOR defined in the
		environment. Otherwise use a default editor based on platform.

def get_editor(self):
		"""
		Give preference to an XML_EDITOR or EDITOR defined in the
		environment. Otherwise use a default editor based on platform.
		"""
		env_search = ['EDITOR']
		if 'xml' in self.content_type:
			env_search.insert(0, 'XML_EDITOR')
		default_editor = self.platform_default_editors[sys.platform]
		return self._search_env(env_search) or default_editor