add configure test for libogg to fix #3278

git-svn-id: https://gnunet.org/svn/gnunet@31971 140774ce-b5e7-0310-ab8b-a85725594a96
-document libogg requirement

git-svn-id: https://gnunet.org/svn/gnunet@31972 140774ce-b5e7-0310-ab8b-a85725594a96
- first extension of paillier with foolproof homomorphism support (ciphertext container carries information on support ops)
- adjusted encryt/decrypt functionality to handle gcry_mpi_t, not a plaintext container

git-svn-id: https://gnunet.org/svn/gnunet@31973 140774ce-b5e7-0310-ab8b-a85725594a96
- header sync

git-svn-id: https://gnunet.org/svn/gnunet@31974 140774ce-b5e7-0310-ab8b-a85725594a96