Merge pull request #249 from maurozucchelli/dsi_metrics_2

Dsi metrics 2
DOC: added slice of gfa together with odfs
RF: cleanup of slicer
NF: added simple camera setter function
BF: A possible bug fix for vtk6's for rendering large images
DOC: typo corrected
BF: outline now works
Merge pull request #251 from Garyfallidis/slicer_odfs_together

Another cleanup for fvtk. This time the slicer function was simplified
added multiprocessing for peaksAndModel function
parallel examples draft
BF: the multi_voxel_model decorator couldn't be pickled and therefore used with multi processing. The solution was to decorate only the fit method and not the entire model.
Updated csdeconv, dsi and gqi to work with the new multi_voxel_fit decorator
change numpy arrays to memmaps to reduce memory usage
cleanup the example
wip
increase the number of job to speedup the computation
cleaned examples code
changed permissions on /dev/shm so that multiprocessing might work
changed /dev/shm to a soft link to /run/shm, trying to fixe mp issue
fixed doctest error in DiffusionSpectrumModel.__init__