dlna_new_item code factorization

the previous code opened twice each file with libavformat, calls some functions more than once in the same sequence.
dlna_guess_media_profile is static now. This function is not used outside profile.c .
av_codec_t contains nb_stream

This modification allows to pass only "codecs" to upnp_guess_media_profile
stream_get_container calls inside probing function

instead to call stream_get_container for each file, the probing function calls it if necessary.
upnp_http_get_info uses directly the mime-type of the profile

instead to build the protocol_info and cut the content-type part, we use directly the mime-type of the profile
dlna_t item doesn't store the file size.

As http.c already checks the size with "stat" function call, cds.c does the same if requested.
This feature allows to check if the file exists before to build the cds information tree.
cds.c check if the file exists before to add protocol_info
new function dlna_item_get(vfs_item_t *) function

Instead to use directly item->u.resource.item, this function returns the pointer.
To use DB this pointer may be NULL and dlna_item_get returns the entry of the DB.
dlna_item_* functions are internal

This functions have internal use only.
dlna_item_get requires dlna_t pointer for future DB access.
move dlna_item_t definition from dlna.h to dlna_internals.h
remove fullpath member of the vfs_item_t structure.

vfs_item_t contained u.resource.fullpath which was a duplication of u.resource.item->filename .
UPnP/AV checks only the file extension to know the profile.

each mime type supported contains the profile. upnp_guess_profile return the address for the extension requested.
remove dlna_item_t .media_class information

the media_class was redundant with the media_class of the profile
dlna_item_t properties are optionals for UPnP/AV

As properties are optionals for UPnP/AV, it's useless to use ffmpeg for UPnp/AV mode.
In UPnp/AV mode the VFS tree is built faster.
the filesize properties storage inside dlna_item_t

As stat function allows to check that the file exists, and doesn't need ffmpeg, we checks the file size.
AVFormatContext must be NULL for avformat_open_input
cds get size from the dlna_item_t properties
dlna_registered_profile_t stores the list of profiles supported
change profiles table access
add sqlite state entry inside config.mak
sqlite db support