MPEG-4: `infe` missing fields for `version == 1`

[archaephyrryx]

(References to ISO/IEC 14496-12 2012)

The implementation of infe_data_ver1 defined in subformats::iinf is marked as // FIXME unfinished.

It is currently missing the fields:

unsigned int(32) extension_type; // optional
ItemInfoExtension(extension_type); // optional

where, for extension_type == 'fdel', the following fields are described:

string content_location;
string content_MD5;
unsigned int(64) content_length;
unsigned int(64) transfer_length;
unsigned int(8) entry_count;
for (i=1; i <= entry_count; i++)
    unsigned int(32) group_id;

It is not clear whether any extension_type values other than 'fdel' are allowed; this should be confirmed before assuming that this is the case.