Show render hierarchy better
Show render hierarchy better

pre_render, _theme() and post_render are called inside of
drupal_render().

DrupalTwig/ThemeSystemDrupalNorth2015,DrupalTwig/ThemeSystemLA2015,DrupalTwig/ThemeSystemAustin2014,DrupalTwig/ThemeSystemLA2015,DrupalTwig/ThemeSystemDrupalNorth2015,DrupalTwig/ThemeSystemBadCamp2014