ogg_afh.c: store bitrate, frequency and channels in struct audio_file info

ogg_afh.c: store bitrate, frequency and channels in struct audio_file info

This patch also contains some other improvements:

	- make sure that we never write beyond the end of the chunk table
	- get rid of some unneeded includes
	- kill pointless raw_total variable
	- get rid of time_total, vi_sampling_rate and vi_bitrate and use
	  the corresponding members of struct audio_file_info directly