Patch for SOCI/soci#46 to support readying bytea data in PostgreSQL
Merge pull request #46 from hobu/issues/46-bytea-read-for-postgis

Preliminary support readying bytea data in PostgreSQL backend as another string type. Keep in mind, data to and from PostgreSQL server is still transfered in textual mode, thus for example stringified and stored bytes of int(0x0A0B0C0D) will be retrieved as std::string("\\x0d0c0b0a"). In future, data transfer may be switched to binary mode, then native binary support will be feasible.