Adding new icon classes

482: .dashicons-microphone
483: .dashicons-universal-access
486: .dashicons-tickets
484: .dashicons-nametag
481: .dashicons-organizer
487: .dashicons-sponsor
488: .dashicons-speaker
489: .dashicons-sessions
501: .dashicons-media-archive
500: .dashicons-media-audio
499: .dashicons-media-code
498: .dashicons-media-default
497: .dashicons-media-document
496: .dashicons-media-interactive
495: .dashicons-media-spreadsheet
491: .dashicons-media-text
490: .dashicons-media-video
492: .dashicons-playlist-audio
493: .dashicons-playlist-video
502: .dashicons-plus-alt
503: .dashicons-randomize