RF: Factor out location information

In anticipation of changes in the OpenFMRI specifications. Now we have
fewer places that make explicit statements about path hierarchy and
filenames.
ENH: Simple accessor for motion estimates
NF: Load arbitrary features/attributes for BOLD timeseries.
NF: add get_anatomy_image function
RF: Adopt get_anatomy_image()
NF: Small demo of a QC command for OpenFMRI dataset motion

This requires the tsboxplot_stuff branch to be merged.

for a demo point to the Forrest Gump dataset with:

pymvpa2 ofmotionqc --path ~/forrest/anondata --estimate-fname bold_dico_moco.txt --outlier-stdthresh 2
Merge pull request #253 from hanke/openfmrids

Refactor openfmri glue code to make it better manageable wrt foreseeable layout changes.