Bugfix for Python 2.4
Checked

That's correct.
No more 'psize' in Writer

Only planes and bitdepth,
pixel size moved to filter object.
cdef methods are private now

To simulate cython restriction in python version
Rework setup\compilation of cython part

Add unimport and it's cleanup to setup.py
Removed precompiled '.c' as this reqire too complex instruction to
update
Removed old cython code (unused now)