Added audio profiles to convert-dlna-scaled-helper.sh, fixed issue with ingest-profiles.txt and itemGen-scaled.sh

convert-dlna-scaled-helper.sh now has references to 4 scaled audio formats
 provided by DLNA: AAC_ADTS_320, AAC_ISO_320, LPCM, and MP3.

Added support to itemGen-scaled.sh to set the "type" property in the item
 file according to the mime type prefix. This allows the resources to
be advertized with the proper UPnP class.

Due to a cut-and-paste error (from the spec), the mime type for AAC_ISO_320
 was incorrect in ingest-profiles.txt.

Adjusted the directory names created by itemGen-scaled.sh. It now generates
 item directories using the profile and content basename and the resource
 subdir is just based on the content basename.

Tested convert-dlna-scaled-helper. All content items/resources appear to be
 generated without error. Verified the mime types and item classes. Did
 some TimeSeekRange/PlaySpeed spot tests for a couple audio and video
 items. They seem to be performing as expected.

Issues/caveats:

 Not sure the resulting binary from a MP3 time-seek (with non-0 start time)
  is legit. VLC won't render the response body.
 Been primarily testing using the --link-content option since (a) it's way
  faster and (b) I don't have enough disk space to copy all the scaled
  content resources. (but haven't observed any issues with the sym linked
  content either).