Install console script only in Py2.x.
Prevent import of the writer in Py3.x.
Change indexer to be able to index Py3 code.

new: PyModuleDef
changed: PyObject_HEAD_INIT
Fix copy paste bug in test class name.
Allow setting version when indexing Python sources.

Try to use the closest match for a version, when looking for available
indexed sources.

Fixes #6.
Use the Python version to be default version for indexes.
Bump up version to 0.2.