patch from ticket #209 to check return value from
PyObject_AsCharBuffer(). This fixes the segfault.
(binary_quote): switch from PyObject_AsCharBuffer() to
PyObject_AsReadBuffer() to support buffer objects that don't
implement the bf_getcharbuf protocol.
* tests/types_basic.py (TypesBasicTests.testBinary): Test round
tripping of bytea buffers. Currently segfaults.
requiring it.
Added a connection flag to store whether E''-style quoting is required: this
avoids repeated PQparameterStatus() calls.
Added a test case to verify correct behavior on strings, unicode and binary
data. Tested with PG versions from 7.4 to 8.3b2, with any server
'standard_conforming_strings' setting and with 'PSYCOPG_OWN_QUOTING' too.