Don't forget to specify mdds flag & fix the build.
Start working on format detection code.

It's just a skeleton for now.
Add xlsx, xls-xml and gnumeric there as well.
Set up testing for detecting ods format.

Right now, it doesn't really detect anything.
Set up skeleton for orcus-detect.
Implement zip_archive_stream_blob.
Detect ods type for real.
Detect xlsx file type.