Fix conversions for inputs of unknown type.

Fix #55
Fix python version detection.
Add missing PYTHON declaration
Add PYTHON_TEST_VERSION for tests remote execution
Make the tests less verbose
Split test between write/no write

This allows tests not to be executed on postgres 9.2
Fix mixup when updating tests.
Fix yet another mistake
Damn symlinks
Add new flag for remote test execution
Add schema option and use when creating sqlalchemy Table instance
Add write support to sqlalchemy fdw
Change the tag from testing to stable
Fix bug when instance initialization fails.
Fix bug with xact callbacks on 9.2
Fix bug on transaction management with 9.2
Version bump
Fix bug in makefile
Add missing errorcheck (fixes #58)
Add missing PY_LDFLAGS.

When using PYTHON_OVERRIDE, some ld flags were missing.
Fixes #62.