Replace checks on fontyourface_detailed_logging variable with calls to fontyourface_log()

For a warm-up, fixed this issue in Edge Fonts, where it had arrived with plagiarized code from some other provider module.

Found one instance in fontsquirrel, four in typekit. Patch attached.

According to our old friend grep, only mentions of fontyourface_detailed_logging related to setting, legitimately using or deleting it are left:

usb@paddock:/var/www/fyf/sites/default/modules/fontyourface$ grep -R -n 'fontyourface_detailed_logging' *
fontyourface.install:288:  variable_del('fontyourface_detailed_logging');
fontyourface.module:684:  if (variable_get('fontyourface_detailed_logging', FALSE)) {
modules/fontyourface_ui/fontyourface_ui.module:563:        '#default_value' => variable_get('fontyourface_detailed_logging', FALSE),
modules/fontyourface_ui/fontyourface_ui.module:645:    variable_set('fontyourface_detailed_logging', TRUE);
modules/fontyourface_ui/fontyourface_ui.module:648:    variable_set('fontyourface_detailed_logging', FALSE);