Remove export, fix documentation
Remove export, fix documentation

Removed the export of defcstruct in fsbv, added copyright and license,
fixed description of file.

mcna/cffi,cffi/cffi,dkochmanski/cffi,stassats/cffi,3b/cffi,cffi/cffi,mcna/cffi,stassats/cffi,attila-lendvai/cffi,attila-lendvai/cffi,stassats/cffi,cffi/cffi,3b/cffi,dkochmanski/cffi,dkochmanski/cffi,3b/cffi