RF: Move boxcar modification from the cmdline into the Python API
BF: OpenFMRI loaded subject model by task ID, needs subject ID
BF+DOC: Fix docs, make run-time test for OpenFMRI schema assumptions
BF: Keep subject info in modeled dataset

Use-case: Load multiple subjects at once. Modeling will be done per subj
run, but no subject info remained in the returned set of datasets.
Merge pull request #251 from hanke/master

Few simple changes