Various refactorings of MRI datasets and analysis.
I refactored some of the functions of the MRI datasets, and also included a dataset for dealing with MRI in transpose.
There is a new analysis script with works with most of the models I'm using without having to worry about specific
methods of extracting features.
Old scripts need to be removed.
Fixed a slight typo where I completely ignore incidices for MRI features.
Merge branch 'nitools' of https://github.com/rdevon/pylearn2 into nitools

Conflicts:
	pylearn2/neuroimaging_utils/tools/mri_analysis.py