tests: cleanup.
Added MultiProcessHdf5File (TODO: docstrings)
OpInputDataReader: Use MultiprocessHdf5File instead of h5py.File
MultiProcessHdf5File: Use Pipe instead of Queue, and pass buffer directly instead of relying on pickle.
OpInputDataReader: Use MultiProcessHdf5Reader for compressed datasets (other datasets wouldn't benefit)
MultiProcessHdf5File: Emit a warning if the dataset isn't compressed.
multiprocessHdf5File: Added METHOD constant for quickly switching between implementations, and added the shared-array implementation for comparison.
Merge branch 'master' into multiprocess-hdf5
Merge branch 'master' into multiprocess-hdf5
Merge branch 'master' into multiprocess-hdf5
Merge branch 'master' into multiprocess-hdf5
Merge branch 'master' of ssh://github.com/ilastik/lazyflow into multiprocess-hdf5
MultiprocessHdf5: Remove lazyflow dependency, added some comments.
Merge branch 'master' into multiprocess-hdf5
Merge branch 'master' into multiprocess-hdf5
TiledVolume: Support RGB images by just extracting the first channel.
Merge branch 'master' into multiprocess-hdf5
TiledVolume: Log the time it takes to fetch blocks of tiles.
TiledVolume: Fixed log message.
TiledVolume: Don't support the non-PIL method that requires tmp files.