Fix auto threshold in img_plotting.py

Replace + by - to ensure that some voxels pass the threshold
Merge pull request #285 from lesteve/auto-threshold

Fix auto threshold in img_plotting.py
Use nilearn plotting in plot_haxby_different_estimators.py
Add colorbar and use default figure size
Parallelization of CanICA
Merge pull request #276 from banilo/par_ica

Parallel() for CanICA class
PEP8 fixes
completed docstrings
corrected add_overlay() docstring
Merge pull request #290 from banilo/doc_thresh

Adding missing 'threshold' docstrings in plotting functions
Use nilearn plotting functions in plot_localizer_simple_analysis.py
restored omitted word
Merge pull request #289 from banilo/ex_affine

PEP8 fixes in plot_affine_transformation.py
Merge pull request #288 from lesteve/use-nilearn-plotting-in-examples

[WIP] Use nilearn plotting functions in examples
Fix bug in fetch_localizer_contrasts when getting T-maps

Added a few tests when setting get_* parameters to True
Use nilearn plotting functions in plot_haxby_mass_univariate.py
Use nilearn plotting functions in plot_localizer_mass_univariate_methods.py
Use nilearn plotting functions in plot_oasis_vbm.py
Use nilearn plotting functions in plot_haxby_masks.py
Fix fetch_haxby with fetch_stimuli=True

data_dir arg was specified twice