MISC: capture meaningless argument in Parallel

Some people actually specify n_jobs=0
WIP: started work on a pool with custom pickler
WIP: more untested work on custom pickler
prototype custom pickling pool is working
Fix wrong docstring + python 2.5 support
Drop useless Unpickler, use HIGHEST_PROTOCOL + fix docstrings
Fix Pool parameter passing to parent class
pep8
More work on automated switch to memmap for large arrays
Cheaper and concurrent safe filenames for dumped arrays
New MemmapingPool for automated shared memory of numpy arrays
MemmapingPool can automatically switch to memmap for large arrays
Better testing for lazy temp folder creation
More tests comments improvements
Make it possible to disable auto-memmaping
Enable new memmap support in the Parallel class
Make it possible to plug custom reducers from the Parallel API
Make it possible to configure the temporary folder as well
One more assertion in the tests
Make ArrayMemmapReducer more robust in case a np.memmap is passed as argument