Revert "Remove more gnutls references."

This reverts commit 6a25507e90c2b2f934724e8eb278e9782acac923.
Revert "libratbox: Remove broken gnutls support."

This reverts commit f2d58c6d72a1735b28ef95566fbd26bb0736246d.
Merge pull request #30 from anarcat/gnutls-restore

Gnutls restore