Callback for fields and validation can now be class-level. Thanks @echo1consulting. Google Fonts no longer require a Google API key unless you want to dynamically update the store. Added new system-wide argument to force google_update_weekly the font cache. Also changed the order of file_system includes to remove an undefined index for submit_button(). Also fixed #1599 by updating Parsedown library. Also fix for issue #1628, spacing and dimensions now only output 0 if 0 is entered (Thanks @Webcreations907).