NF: make SPM processing example for Open FMRI ds107

Example of how to batch script SPM5 (!) preprocessing for the Open FMRI ds107
dataset.
RF: refactor SPM batch script for study params

Allow passing of study and analysis parameter dictionaries.
RF: pass through if is non-gzipped nifti already
Allow bare .nii files instead of .nii.gz
Add prefix input output
RF: throw out duplicate filenames, nii; nii.gz
RF: allow zero anatomicals
fix 2-level glm implementation and move it to nipy.algorithms
re-implement parcel-based group analysis method (Keller et al, Statistica Sinica 2008; Roche, OHBM'12 talk)
account for Bertrand's PR review
remove old parcel-based group analysis code from labs
Account for Matthew's PR review
increase test coverage
raise test coverage to 92%
raise test coverage for parcel_analysis.py (99%) and bayesian_mixed_effects (100%)
RF: adapt script to ds105

Fix some bugs in script too.
RF: update spm interface for SPM8 batch jobs

SPM8 batch jobs need extra 'initcfg' step to spm_jobman

Add SPM version check to decided whether to add this initcfg step.
RF: update ds105 example for SPM8 batching
DOC: point to nipype for extended use
Merge pull request #292 from alexis-roche/refactor-group-analysis

MRG: Refactor group analysis

A fast re-implementation of the parcel-based group analysis method proposed in Keller et al (Statistica Sinica 2008, MICCAI 2009); moving implementation from nipy.labs to nipy.algorithms.